Parameters


nameunittypeprecisiondescriptionnotesrequiredScope
subsurfaceTemp20cmCelsiusfloat1The temperature measured 15-34 centimeters below the surface, typically in soil or other substrates.None
subsurfaceTemp5cmCelsiusfloat1The temperature measured 7 centimeters or less below the surface, typically in soil or other substrates.None
surfaceConductivity4mhos/cmfloat2An RWIS parameter. Indicates the ability of the road surface to conduct electrical current, which can be useful for assessing the presence of moisture, salts, or other substances that affect road conditions.None
surfaceConductivity5mhos/cmfloat2An RWIS parameter. Indicates the ability of the road surface to conduct electrical current, which can be useful for assessing the presence of moisture, salts, or other substances that affect road conditions.None
surfaceConductivity3mhos/cmfloat2An RWIS parameter. Indicates the ability of the road surface to conduct electrical current, which can be useful for assessing the presence of moisture, salts, or other substances that affect road conditions.None
surfaceConductivity2mhos/cmfloat2An RWIS parameter. Indicates the ability of the road surface to conduct electrical current, which can be useful for assessing the presence of moisture, salts, or other substances that affect road conditions.None
surfaceConductivity6mhos/cmfloat2An RWIS parameter. Indicates the ability of the road surface to conduct electrical current, which can be useful for assessing the presence of moisture, salts, or other substances that affect road conditions.None
subsurfaceTemp5Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
surfaceTemp7Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
surfaceTemp9Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
pressureChange3HourhPAfloat0The change in air pressure over a 3-hour period.None
waterThicknessmmfloat2The measurement of the depth of water or water film on a surface, such as a roadway or pavement.None
surfaceCondition1integer2Describes the current state of a surface, such as roads or bridges, based on weather and environmental factors.None
surfaceTemp11Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
surfaceTemp12Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
precipIntensitystring2Measures the rate at which precipitation (rain, snow, etc.) is falling, typically in millimeters per hour or inches per hour. None
windChillCelsiusfloat2Represents the perceived decrease in air temperature felt by the skin due to the combined effect of wind and cold temperature.None
sunriseUTCstring2UTC time of sunrise for this station on the valid date.Not directly observed - derived from the station position.read:one-observations-public, weather.observations.core:read
precipAcc6Hourmmfloat2Amount of liquid precipitation (typically rain) measured in the 6 hours before the valid timestamp.Noneread:one-observations-public, weather.observations.core:read
chemicalFactorn/afloat2A numerical value indicating the effectiveness of de-icing or anti-icing chemicals applied to the road surface.None
chemicalPercentpercentfloat2The percentage of chemical concentration present on the road surface. It represents the proportion of de-icing chemicals (such as salt brine or calcium chloride) in the surface moisture.None
icePercentpercentfloat2The proportion of ice relative to the total surface moisture on the road.None
surfaceConditionstring2Describes the current state of a surface, such as roads or bridges, based on weather and environmental factors.None
subsurfaceTemp10Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
subsurfaceTemp2Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
subsurfaceTemp50cmCelsiusfloat1The temperature measured 35-74 centimeters below the surface, typically in soil or other substrates.None
precipTypestring0Identifies the type of precipitation occurring, such as rain, snow, sleet, or hail.None
metarWxcodecode2Plain English description of present weather conditions derived directly from METAR code.Example: ‘+TS’ in original METAR would be expressed as ‘heavy thunderstorm’
snowDepthmmfloat2The measure of accumulated snow thickness on the ground surface in millimeters.This is total snow depth at a given time, not freshly added snow over a period.
waterLevelmmfloat2NoneNone
subsurfaceTemp100cmCelsiusfloat1The temperature measured 75-149 centimeters below the surface, typically in soil or other substrates.None
subsurfaceTemp10cmCelsiusfloat1The temperature measured 8-14 centimeters below the surface, typically in soil or other substrates.None
subsurfaceTemp150cmCelsiusfloat1The temperature measured 150 centimeters or more below the surface, typically in soil or other substrates.None
cloudBasemfloat1The observed altitude of the base of the clouds, aka ceiling height.When we talk about a cloud base of 3,000 ft, we usually mean that there is broken or more cloud from 3,000 ft.
relativeHumiditypercentfloat0Relative humidity represents the ratio of the actual amount of water vapour in the air to the maximum amount that can physically exist at a given air temperature.Exact height of measurement is 2m for networks which conform to WMO standards (Metar and Synop). This cannot be guaranteed for all sources but deviations in air temperatures at most surface measurement heights will be trivial.
windGust2mm/sfloat2Wind gust speed 2m above the surface, normally a 3 second average sampled in the 10 minute before the valid timestamp.This height is an approximation for data sources where we know or it is reasonable to assume that winds will be measured closer to 2m than 10m. As a general rule 10m wind speeds will be 30% higher than 2m.read:one-observations-public, weather.observations.core:read
windGustm/sfloat2Wind gust speed 10m above the surface, normally a 3 second average sampled in the 10 minute before the valid timestamp.Exact height of measurement is 10m for networks which conform to WMO standards (METAR and SYNOP).read:one-observations-public, weather.observations.core:read
windDirectionAvg24Hourdegreefloat0Wind direction averaged over the 24 hours before the valid timeNoneread:one-observations-public, weather.observations.core:read
windDirectiondegreefloat0Compass direction the corresponding windSpeed10m is coming from.Exact height of measurement is 10m for networks which conform to WMO standards (METAR and SYNOP).read:one-observations-public, weather.observations.core:read
visibilitykmfloat2Horizontal visibility.Maximum visibility value may vary depending on source.read:one-observations-public, weather.observations.core:read
sunshine60MinminutesintegerNoneNumber of minutes of sunshine (sun unobscured by cloud) over the hour before the observation time.Noneread:one-observations-public, weather.observations.core:read
sunshine24HourminutesintegerNoneNumber of minutes of sunshine (sun unobscured by cloud) over the 24 hours before the observation time.Noneread:one-observations-public, weather.observations.core:read
seaSurfaceTempCelsiusfloat1The temperature of the seawater at or near the surface, measured at coastal or offshore locations. None
dewPointMin2mCelsiusfloat1NoneNone
subsurfaceTemp8Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
surfaceTemp10Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
altimeterhpafloat2Air pressure corrected to / valid at mean sea level for the purpose of aircraft instrument calibration.Roughly equivalent to pressureMsl but will start to deviate significantly at higher elevations (>1km)
precipRatemm/hrfloat2Precipitation rate or intensity, in mm per hour.Can be effectively taken as precipAcc60Min (mm) assuming the precip at observed time was constant over the previous hour. If precipRate is given every 10 minutes, divide by 6 to get precipAcc10Min equivalent.
coolingDegreeUS24HourCelsiusfloat1Degree days indicating cooling demand based on outdoor temperatures; calculated when average daily temperature is above 65°F (18.3°C).None
surfaceTempCelsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
wbgtCelsiusfloat1Wet Bulb Globe Temperature (WBGT) is a measure of the heat stress in direct sunlight, which takes into account: temperature, humidity, wind speed, sun angle and cloud cover (solar radiation).None
heatingDegreeUS24HourCelsiusfloat1Degree days indicating heating demand based on outdoor temperatures; calculated when average daily temperature is below 65°F (18.3°C).None
windSpeed2mm/sfloat2Wind speed 2m above the surface, normally averaged over 10 minutes.This height is an approximation for data sources where we know or it is reasonable to assume that winds will be measured closer to 2m than 10m. As a general rule 10m wind speeds will be 30% higher than 2m.read:one-observations-public, weather.observations.core:read
windGust3Hourm/sfloat2Maximum observed wind gust speed 10m above the surface during the 3 hours before the valid timestamp.Exact height of measurement is 10m for networks which conform to WMO standards (METAR and SYNOP).read:one-observations-public, weather.observations.core:read
windDirection2mdegreefloat0Compass direction the corresponding windSpeed2m is coming from.This height is an approximation for data sources where we know or it is reasonable to assume that winds will be measured closer to 2m than 10m. As a general rule 10m wind speeds will be 30% higher than 2m.read:one-observations-public, weather.observations.core:read
soilMoisturepercentfloat2The moisture level of the soil.Stations may have multiple sensors and depths, currently the api exposes the deepest value available. In future multiple depths and sensors will be supported.
metarSkycodestringNoneRaw METAR code describing cloud cover, height and type - used for aviation purposes.Example: FEW005 SCT010CB BKN025 means 'few at five hundred feet, scattered cumulonimbus at one thousand feet, broken at two thousand five hundred feet'. Up to three, but occasionally more, cloud groups may be reported. Further decoding information is widely available online.
precipAcc3Hourmmfloat2Amount of liquid precipitation (typically rain) measured in the 3 hours before the valid timestamp.Noneread:one-observations-public, weather.observations.core:read
precipAcc12Hourmmfloat2Amount of liquid precipitation (typically rain) measured in the 12 hours before the valid timestamp.Noneread:one-observations-public, weather.observations.core:read
precipAcc10Minmmfloat2Amount of liquid precipitation (typically rain) measured in the 10 minutes before the valid timestamp.Noneread:one-observations-public, weather.observations.core:read
surfaceConductivitymhos/cmfloat2An RWIS parameter. Indicates the ability of the road surface to conduct electrical current, which can be useful for assessing the presence of moisture, salts, or other substances that affect road conditions.None
sunsetUTCstring2UTC time of sunset for this station on the valid date.Not directly observed - derived from the station position.read:one-observations-public, weather.observations.core:read
globalRadiation60Minjoules per square centimeterfloatNoneSolar radiation integrated over the previous hour.This can be effectively converted to the instantaneous solarRadiation by dividing by 0.36, assuming the radiation at the end of the hour = the average of the previous hour.read:one-observations-public, weather.observations.core:read
globalRadiation24Hourjoules per square centimeterfloatNoneTotal solar radiation accumulated over the past 24 hours.Can be reported at source or aggregated by our API over any daily period by specifying interval=24h in observations endpoint.read:one-observations-public, weather.observations.core:read
soilTempCelsiusfloat1Temperature of soil at a given depth.Stations may have multiple sensors and depths, currently the api exposes the deepest value available. In future multiple depths and sensors will be supported.
cloudCoverpercentfloat2Percentage of the sky covered by cloud. 100% = overcast, 0% = blue sky.Not to be confused with ‘effective cloud cover’. Sky can still be bright with 100% totalCloud if cloud is high/thin. For Metars this parameter is derived from given cloud groups (SCT/BKN etc.) therefore has limited precision. Multiply by 0.08 to convert to oktas.read:one-observations-public, weather.observations.core:read
airTempMin24HourCelsiusfloat1Minimum air temperature 2m above the surface, measured in the 24 hours before the valid time.Can be reported at source or aggregated by our API over any daily period by specifying interval=24h in observations endpoint.read:one-observations-public, weather.observations.core:read
airTempMax24HourCelsiusfloat1Maximum air temperature 2m above the surface, measured in the 24 hours before the valid time.Can be reported at source or aggregated by our API over any daily period by specifying interval=24h in observations endpoint.read:one-observations-public, weather.observations.core:read
airTempMax12HourCelsiusfloat1Maximum air temperature 2m above the surface, measured in the 12 hours before the valid time.Reported at source. We do not currently aggregate data from lower time periods to higher time periods.read:one-observations-public, weather.observations.core:read
airTemp5cmCelsiusfloat1Temperature measured near the ground at a height of 5 centimetres.Available predominately via DTN EU networkread:one-observations-public, weather.observations.core:read
airTempCelsiusfloat1Instantaneous air temperature 2m above the surface.Exact height of measurement is 2m for networks which conform to WMO standards (Metar and Synop). This cannot be guaranteed for all sources but deviations in air temperatures at most surface measurement heights will be trivial.read:one-observations-public, weather.observations.core:read
airTempMax1HourCelsiusfloat1Maximum air temperature 2m above the surface, measured in the 1 hour before the valid time.Reported at source. We do not currently aggregate data from lower time periods to higher time periods.read:one-observations-public, weather.observations.core:read
surfaceTemp4Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
surfaceTemp8Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
frictionmufloat2Refers to the grip or traction between the road surface and tires of vehiclesNone
gradtagzahl24HourCelsiusfloat1German heating degree day, with a base temperature of 22C, only calculated when daily average airTemp falls below 15. Valid for Kalendertag if 00-00 UTC, Gastag if aggregated 06-06 local time.None
gradtagzahlBasic24HourCelsiusfloat1German heating degree day, with a base temperature of 20C, only calculated when daily average airTemp falls below 15. Valid for Kalendertag if 00-00 UTC, Gastag if aggregated 06-06 local time. None
windSpeedm/sfloat2Wind speed 10m above the surface averaged over 10 minutes.Exact height of measurement is 10m for networks which conform to WMO standards (METAR and SYNOP).read:one-observations-public, weather.observations.core:read
shortWaveRadiationwatts per square meterfloat2Instantaneous solar (direct plus diffuse) radiation. Also called GHI.This can be effectively converted to globalRadiation60Min (Jcm2) by multiplying by 0.36, assuming the solarRadiation at observed time was constant over the previous hour.
sunshine10MinminutesfloatNoneNumber of minutes of sunshine (sun unobscured by cloud) over the 10 minutes before the observation time.Noneread:one-observations-public, weather.observations.core:read
precipAcc60Minmmfloat2Amount of liquid precipitation (typically rain) measured in the 1 hour before the valid timestamp.We do not currently sum or aggregate from sub-hourly precipitation to get to precip60Min but this is often done at source. The parameter ‘precip’ is a value for accumulated precipitation and may also be useful although its exact definition depends on its source.read:one-observations-public, weather.observations.core:read
precipAcc24Hourmmfloat2Amount of liquid precipitation (typically rain) measured in the 24 hours before the valid timestamp.Can be reported at source or aggregated by our API over any daily period by specifying interval=24h in observations endpoint. Values from NOAA_GHCND are stored with default timestamp 1111UTC where the true timestamp is not known.read:one-observations-public, weather.observations.core:read
dewPointCelsiusfloat1Dew point temperature 2m above the surface. The temperature to which the air must be cooled for saturation and condensation to occur.Exact height of measurement is 2m for networks which conform to WMO standards (Metar and Synop). This cannot be guaranteed for all sources but deviations in air temperatures at most surface measurement heights will be trivial.read:one-observations-public, weather.observations.core:read
seaWaterTempCelsiusfloat1The temperature of the water close to the ocean’s surface.None
waveDirectiondegreesfloatNoneThe mean direction of ocean/sea surface waves generated by local winds and swell.None
wavePeakPeriodsecondsfloat2The period of the most energetic waves where period is the time it takes for two consecutive wave crests, on the surface of the ocean/sea, to pass through a fixed point.None
seaWaterSalinityg/kgfloat2The salt concentration in sea water.None
eastwardCurrentm/sfloatNoneThe speed of the component of the sea current travelling towards the east. Negative is westerly.None
northwardCurrentm/sfloatNoneThe speed of the component of the sea current travelling towards the north. Negative is southerly.None
significantWaveHeightmetresfloat2The mean wave height (trough to crest) of the highest third of the waves.None
leafWetnessindexfloat2Presence of surface moisture on a crop.With range from 0 (completely dry) to 15 (saturated).
wmoWeatherCodecodeinteger0WMO weather code corresponding to table 4677.See reference table on https://www.nodc.noaa.gov/archive/arc0021/0002199/1.1/data/0-data/HTML/WMO-CODE/WMO4677.HTMread:one-observations-public, weather.observations.core:read
windGust6Hourm/sfloatNoneMaximum observed wind gust speed 10m above the surface during the 6 hours before the valid timestamp.Exact height of measurement is 10m for networks which conform to WMO standards (METAR and SYNOP).read:one-observations-public, weather.observations.core:read
windGust60Minm/sfloat2Maximum observed wind gust speed 10m above the surface during the 1 hour before the valid timestamp.Exact height of measurement is 10m for networks which conform to WMO standards (METAR and SYNOP).read:one-observations-public, weather.observations.core:read
wmoWeatherCode4680codeinteger0WMO weather code corresponding to table 4680.Limited availability, use wmoWeatherCode in most cases.
windSpeedAvg24Hourm/sfloat2Wind speed 10m above the surface, averaged over the 24 hours before the valid timeNoneread:one-observations-public, weather.observations.core:read
windGustMax24Hourm/sfloat2Maximum wind gust speed 10m above the surface, observed in the 24 hours before the valid time.Noneread:one-observations-public, weather.observations.core:read
wetBulbCelsiusfloat1The temperature read by a well-ventilated thermometer covered in water-soaked cloth.At 100% relative humidity, the wet-bulb temperature is equal to the air temperature; at lower humidity the wet-bulb temperature is lower than dry-bulb temperature because of evaporative cooling.
fuelMoisturepercentfloat2Fuel moisture is a measure of the amount of water in a fuel (vegetation) available to a fire
subsurfaceTemp13Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
subsurfaceTemp15Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
subsurfaceTemp4Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
subsurfaceTemp6Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
subsurfaceTemp7Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
subsurfaceTemp9Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
subsurfaceTemp11Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
surfaceTemp5Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
freshSnowDepthmmfloat2The newly added / fresh amount of of accumulated snow in millimeters, since the last observation.This is freshly added snow, for total snow depth use snowDepth.
airTemp5cmMax1HourCelsiusfloat1Maximum temperature measured near the ground at a height of 5 centimetres, over the past 1 hour.None
airTemp5cmMin1HourCelsiusfloat1Minimum temperature measured near the ground at a height of 5 centimetres, over the past 1 hour.None
airTemp5cmMin24HourCelsiusfloat1Minimum temperature measured near the ground at a height of 5 centimetres, over the past 24 hours.None
subsurfaceTemp14Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
subsurfaceTemp12Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
subsurfaceTemp3Celsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
surfaceTemp2Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
airTempMin1HourCelsiusfloat1Minimum air temperature 2m above the surface, measured in the 1 hour before the valid time.Reported at source. We do not currently aggregate data from lower time periods to higher time periods.read:one-observations-public, weather.observations.core:read
airTempMin12HourCelsiusfloat1Minimum air temperature 2m above the surface, measured in the 12 hours before the valid time.Reported at source. We do not currently aggregate data from lower time periods to higher time periods.read:one-observations-public, weather.observations.core:read
subsurfaceTempCelsiusfloat1The temperature measured below the surface, typically in soil, rock, or other underground materials.None
surfaceTemp6Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
airTemp5cmMax12HourCelsiusfloat1Maximum temperature measured near the ground at a height of 5 centimetres, over the past 12 hours.None
airTemp5cmMax24HourCelsiusfloat1Maximum temperature measured near the ground at a height of 5 centimetres, over the past 24 hours.None
airTemp5cmMin12HourCelsiusfloat1Minimum temperature measured near the ground at a height of 5 centimetres, over the past 12 hours.
feelsLikeTempCelsiusfloat1The equivalent human perceived temperature, taking into account the combined effects of air temperature, relative humidity and wind speed.When airTemp is less than or equal to 10 celsius, feelsLikeTemp is synonymous with windChill. If airTemp is great than or equal to 27, its synonymous with heatIndex.read:one-observations-public, weather.observations.core:read
airTempAvg24HourCelsiusfloat1Air temperature 2m above the surface, averaged over the 24 hours before the valid timeNoneread:one-observations-public, weather.observations.core:read
surfaceTemp3Celsiusfloat1Temperature of the road (pavement) surface, usually used for winter road maintenance.RWIS stations often have multiple sensors, where a station has more than 1 these are labelled as surfaceTemp2 to surfaceTemp6. surfaceTemp is not exclusive to networkType RWIS, other networkTypes may have this parameter.
mslPressurehPAfloat0Air pressure corrected to / valid at mean sea level.Roughly equivalent to altimeter but will start to deviate significantly at higher elevations (>1km)
stationPressurehPAfloat0Air pressure valid at station’s elevation.Noneread:one-observations-public, weather.observations.core:read
freezingTempCelsiusfloat1A parameter that indicates the threshold air temperature at or below which water freezes. Typically used to detect freeze events that can affect agriculture, road safety, infrastructure, and ecosystems.None