WeatherSentry API
This overview is intended for users of WeatherSentry API tabular data service, exposed using the REST design architecture. Included in this overview are the various parameters available to users. For additional details, please see the Programming with the WeatherSentry® REST Service
All requests can be made by requesting a Station ID, postal code, or latitude and longitude.
WeatherSentry API provides your organization with global weather observations and forecasts. All content is global unless otherwise stated.
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Hourly Parameters
Hourly weather data is available as observations or forecasts made each hour (hh:) between 15 minutes before the top of the hour (hh-1:45) and the top of the hour (hh:00). Hourly observations are available for the past 60 days, and forecasts are available for every hour from the next hour of today out to 15 days from today.
Multiple units of measure are available. For example; temperature is typically measured in degrees Fahrenheit or degrees Celsius. Refer to the XSD at (http://weather.dtn.com/rest-3.4/doc/TDTNWeatherDataService.xsd) for valid values. Most hourly parameters are available for both forecast (Fcst) and observed (Obs); with exceptions noted in the table below.
If the start or end dates of the request falls out of the allowed date time range (past 60 days for observations, next 15 days for forecasts), the service will return a fault code indicating the allowed date time range.
Refer to the XSD for fault codes (http://weather.dtn.com/rest-3.4/doc/fault.xsd).
| Hourly Parameter | Description | Fcst | Obs |
|---|---|---|---|
| Temperature | The air temperature. | √ | √ |
| Dew Point | The air temperature at which the air will become saturated, and dew moisture will condense into fog (or dew). | √ | √ |
| Relative Humidity | The amount of water vapor in the air compared to how much it could hold at this temperature (percentage). | √ | √ |
| Heat Index | The combination of air temperature and relative humidity determining a perceived air temperature. | √ | √ |
| Wind Chill | The combination of air temperature and wind speed determining a perceived air temperature. | √ | √ |
| Feels Like | The feels like temperature combines the heat index and wind chill into a single temperature value. | √ | √ |
| Wind Direction | The direction the wind is coming from, rounded to the nearest 10 degrees of compass heading. | √ | √ |
| Wind Speed | The sustained speed of the wind as measured at 10m (33ft) for official airport locations, or at 2.5m (7ft) for unofficial and agricultural locations. | √ | √ |
| Wind Gusts | The speed of wind gusts (if reported, this is the peak instantaneous wind speed observed in the 10 minutes prior to the observation). | √ | √ |
| Wet Bulb Temp | The lowest temperature that can be reached by the evaporation of water only. | √ | √ |
| Minutes of Sunshine | The number of minutes of sunshine observed. | √ | √ |
| Cloud Cover Percentage | The percentage of sky covered by clouds. | √ | √ |
| Solar Radiation | The Global Horizontal Irradiance (GHI) in Watts/m2. | √ | √ |
| Probability of Precipitation | The probability of any kind of precipitation to occur. | √ | |
| Precipitation amount | Total of rain, ice, or snowfall. | √ | √ |
| Snowfall | The amount of snowfall. | √ | √ |
| Precipitation Type | The type of precipitation (rain, ice or snow). | √ | √ |
| Weather Description | The general weather condition. | √ | √ |
| Sea Level Pressure | The atmospheric pressure reduced to mean sea level. | √ | √ |
| Visibility | Distance visible without instrumental assistance. | √ | √ |
| Weather Code | The coded value for the general weather condition (see valid values in XSD). | √ | √ |
| Observed Time | The time of observation. | √ | |
| Soil Temperature | a collection of up to four soil temperature values at different depth levels | √ | |
| Soil Moisture | a collection of up to four soil moisture values at different depth levels. | √ | |
| Leaf Wetness | a collection of up to four leaf wetness values at different depth levels. | √ | |
| Leaf Temperature | This value is no longer supported. | √ |
Daily Parameters
Daily weather data is available as observations or forecasts made for each day, defined as the period from local midnight to local midnight at each location. Daily observations are available for the past 2 or 5 years (depending upon the subscription) in 60 day increments, and forecasts are available for every day from the remainder of today out to 15 days from today.
Multiple units of measure are available. Refer to the XSD at (http://weather.dtn.com/rest-3.4/doc/TDTNWeatherDataService.xsd) for valid values. Daily parameters are valid for a given location and a specified local calendar day; that is midnight to 11:59 pm local time. Most daily parameters are available for forecast (Fcst) – the next 15 days, observed (Obs) – the past 60 days, and Historical (Hist) – the past 5 years; with exceptions noted in the table below.
If the start or end dates of the request falls out of the allowed date time range (past 60 days for observations, 15 next days for forecasts, 5 years for historical), the service will return an error indicating the allowed date time range. In the case of historical observations, the range is 2 or 5 years (depending on the subscription) using a 60 days window, any request out of the allowed range or the 60 days window will return a fault code.
Refer to the XSD for fault codes (http://weather.dtn.com/rest-3.4/doc/fault.xsd).
| Daily Parameter | Description (by calendar day) | Obs | Fcst | Hist |
|---|---|---|---|---|
| Sunrise | The time at which the first part of the sun becomes visible in the morning. | √ | √ | √ |
| Sunset | The time at which the last part of the sun disappears below the horizon in the evening. | √ | √ | √ |
| Maximum Temperature | The highest (warmest) temperature to occur in the day. | √ | √ | √ |
| Minimum Temperature | The lowest (coldest) temperature to occur in the day. | √ | √ | √ |
| Average Temperature | An average of the Maximum Temperature and the Minimum Temperature. | √ | √ | √ |
| Average Dew Point | An average of the 24 hourly dew point values. | √ | √ | |
| Average Relative Humidity | An average of the 24 hourly relative humidity values. | √ | √ | |
| Average Wet Bulb Temperature | An average of the 24 hourly wet bulb temperature values. | √ | √ | |
| Heating Degree Day (HDD) | The sum of heating degrees required to maintain an average temperature of 65°F (18°C) within a home or business. | √ | √ | √ |
| Cooling Degree Day (CDD) | The sum of cooling degrees required to maintain an average temperature of 65°F (18°C) within a home or business. | √ | √ | √ |
| Effective Degree Day | Effective Degree Day is a proprietary, enhanced version of Heating Degree Day that adds the effect of wind speed. | √ | √ | √ |
| Average Heat Index | An average of the 24 hourly heat index temperatures. | √ | √ | √ |
| Minimum Heat Index | The lowest hourly heat index temperature. | √ | √ | √ |
| Maximum Heat Index | The highest hourly heat index temperature. | √ | √ | √ |
| Average Wind Chill | An average of the 24 hourly wind chill temperatures. | √ | √ | √ |
| Minimum Wind Chill | The lowest wind chill value. | √ | √ | √ |
| Maximum Wind Chill | The highest wind chill value. | √ | √ | √ |
| Average Feels Like | An average of the 24 hourly feels like temperatures. | √ | √ | |
| Maximum Feels Like | The highest feels like temperature to occur. | √ | √ | √ |
| Minimum Feels Like | The lowest feels like temperature to occur. | √ | √ | √ |
| Average Wind Speed | An average of the 24 hourly wind speed values. | √ | √ | |
| Maximum Wind Speed | The highest wind speed or gust value for the day. | √ | √ | √ |
| Minutes of Sunshine | The number of minutes of sunshine to occur. | √ | √ | √ |
| Solar Radiation | The 24 hour average Global Horizontal Irradiance (GHI) in Watts/m2, including the effect of cloud cover. | √ | √ | √ |
| Cloud Cover Percentage | The average percentage of sky covered by clouds. | √ | √ | |
| Evapotranspiration | The daily total of evaporation and plant transpiration from the earth’s land surface assuming a grass cover (based on the FAO 56 Penman-Monteith calculation) | √ | √ | √ |
| Growing Degree Day | The sum of degree days above an average temperature of 50°F (10°C) used for corn. | √ | √ | √ |
| Probability of Precipitation | The probability of any kind of precipitation to occur. | √ | ||
| Precipitation amount | Total precipitation quantity (rain, ice, or snow). | √ | √ | √ |
| Snowfall | The amount of snowfall. | √ | √ | √ |
| Precipitation Type | Type of precipitation; rain, ice or snow. | √ | √ | √ |
| Weather Description | The general weather condition. | √ | √ | √ |
| Crop Heating Unit | Crop Heat Units is an energy term calculated daily using the daily maximum and minimum temperature | √ | √ | √ |
| Average Barometric Pressure | An average of the 24 hourly barometric pressure. | √ | √ | |
| Average Soil Moisture | The estimated soil moisture content at a 4 inch depth. | √ | √ | |
| Minimum Soil Moisture | The lowest estimated soil moisture content in the day. | √ | √ | |
| Maximum Soil Moisture | The highest estimated soil moisture content. | √ | √ | |
| Average Soil Temperature | The estimated soil temperature. | √ | √ | |
| Minimum Soil Temperature | The lowest estimated soil temperature. | √ | √ | |
| Maximum Soil Temperature | The highest estimated soil temperature.. | √ | √ | |
| Average Wet Bulb Globe Temperature | The average of the 24 hourly Wet Bulb Globe temperatures. | √ | √ | √ |
| Minimum Wet Bulb Globe Temperature | The lowest Wet Bulb Globe temperature measured. | √ | √ | √ |
| Maximum Wet Bulb Globe Temperature | The highest Wet Bulb Globe temperature measured | √ | √ | √ |
| Weather Code | The coded value for the general weather condition (see valid values in XSD). | √ | √ | √ |
| Soil Temperatures | a collection of up to four average, maximum and minimum soil temperature values | √ | √ | |
| Soil Moisture | a collection of up to four average, maximum and minimum soil moisture values | √ | √ | |
| Leaf Wetness | a collection of up to four average, maximum and minimum leaf wetness values | √ | √ | |
| Leaf Temperature | a collection of up to four average, maximum and minimum leaf temperature | √ | √ |
Daily Normals
Daily Normal readings are available for 10 year period with Daily Interpolated (intr) and Daily Observation (Abs).
If the start or end dates of the request falls out of the allowed date time range (from the past 60 days to the next 15 days), the service will return a fault code indicating the allowed date time range.
Refer to the XSD for fault codes (http://weather.dtn.com/rest-3.4/doc/fault.xsd).
Multiple units of measure are available. Refer to the XSD at (http://weather.dtn.com/rest-3.4/doc/TDTNWeatherDataService.xsd) for valid values.
| Daily Parameter | Description (by calendar day) |
|---|---|
| 10yr Normal Maximum Temperature | An average of the high temperatures recorded for a calendar day over a 10 year period. |
| 10yr Normal Minimum Temperature | An average of the low temperatures recorded for a calendar day over a 10 year period. |
| 10yr Normal Average Temperature | An average of the Normal Maximum Temperature and Normal Minimum Temperature over a 10 year period. |
| Average Temperature Departure From 10yr Normal | The difference between the Average Temperature and the 10yr Normal Average Temperature for the same calendar day. |
| 10yr Normal Heating Degree Day | An average of the number of heating degrees recorded for the same calendar day over a 10 year period. |
| Heating Degree Day Departure From 10yr Normal | The difference between the number of heating degrees and the 10yr Normal Heating Degree Day for the same calendar day. |
| 10yr Normal Cooling Degree Day | An average of the number of cooling degrees recorded for the same calendar day over a 10 year period. |
| Cooling Degree Day Departure From 10yr Normal | The difference between the number of cooling degrees and the 10yr Normal Cooling Degree Day for the same calendar day. |
| 10yr Normal Effective Degree Day | An average of the number of effective degrees recorded for the same calendar day over a 10 year period. |
| Effective Degree Day Departure From 10yr Normal | The difference between the number of effective degrees and the 10yr Normal Effective Degree Day for the same calendar day. |
Interpolated Data Service (IDS)
This request will return interpolated data in observation or forecast context. Interpolated information is obtained by taking a weighted average of data from known stations in the area of the request. The IDS also allows queries over a span of time, and returns accumulations, which is especially useful for determining the weather over a growing season, or between specific dates (e.g. how much rain has fallen since I planted my crop?). Alternatively, the IDS can deliver a list of individual daily values instead of a single accumulated value, for each parameter. For a list of available parameters, please refer to the XSD.
Results vary depending the station access level for the given account. That is, some accounts have their own stations (clubs) which are automatically factored into the request.
Special considerations for weather station clubs
DTN operates several weather station networks whose observations are proprietary. A group of weather stations that are proprietary are considered to belong to a Club. Customers using the IDS who have permission to view weather stations within one or more clubs will see those stations included in the IDS calculations.
Precipitation is calculated using a special algorithm to handle the discontinuous nature of precipitation data, as follows:
For club weather station members
- If there is a club station within .5km it will use that stations data
- If there is NOT a club station <.5km away, it will look up for any stations within a radius of 30km
- All stations within 30km radius will be processed as follows :
- Compute bias => (location value – station value) * (1- station distance/30km)
- Compute IDW (inverse distance weighting) of bias values
- Subtract the bias value from the IDW to the location value
- If there are no stations within 30KM, it will use gridded data source only
For non-club station members
- For continental United States + Canada it will use available radar-estimated data only
- Requests outside continental United States + Canada or areas where there are no radar estimates available, value is computed using the 6 closest stations using inverse distance weighting
Multiple units of measure are available. Refer to the XSD at (http://weather.dtn.com/rest-3.4/doc/TDTNWeatherDataService.xsd) for valid values. Interpolated parameters are returned for forecast (Fcst) – the next 15 days, observed (Obs) – the past 60 days, and Historical (Hist) – the past 5 years; with exceptions noted in the table below.
| Daily Parameter | Description | Obs | Fcst | Hist |
|---|---|---|---|---|
| Evapotranspiration | .The daily total of evaporation and plant transpiration from the earth’s land surface assuming a grass cover (based on the FAO 56 Penman-Monteith calculation) | √ | √ | √ |
| Growing Degree Day | The sum of degree days above an average temperature of 50°F (10°C) used for corn. | √ | √ | √ |
| Precipitation amount | Total liquid equivalent precipitation quantity (rain, ice, or snow). | √ | √ | √ |
| Crop Heating Unit | Crop Heat Units is an energy term calculated daily using the daily maximum and minimum temperature | √ | √ | √ |
| Solar Radiation | The 24 hour average Global Horizontal Irradiance (GHI) in Watts/m2, including the effect of cloud cover | √ | √ | √ |
| Precipitation Amount List | Total liquid equivalent precipitation quantity (rain, ice, or snow), returned as a list of individual daily values. | √ | √ | |
| Crop Heating Unit List | A list of crop heating unit measures in hourly increments dependent on time frame requested, returned as a list of individual daily values… | √ | √ | |
| Evapotranspiration List | The daily total of evaporation and plant transpiration from the earth’s land surface assuming a grass cover (based on the FAO 56 Penman-Monteith calculation) , returned as a list of individual daily values. | √ | √ | |
| Growing Degree Day list | The sum of degree days above an average temperature of 50°F (10°C) used for corn, returned as a list of individual daily values.. | √ | √ | |
| Maximum Temperature | The highest (warmest) temperature to occur in the day. | √ | √ | √ |
| Minimum Temperature | The lowest (coldest) temperature to occur in the day. | √ | √ | √ |
| Maximum Relative Humidity | The highest relative humidity to occur in the day. | √ | √ | √ |
| Minimum Relative Humidity | The lowest relative humidity to occur in the day. | √ | √ | √ |
| Average Wind Speed | An average of the 24 hourly wind speed values. | √ | √ | √ |
| Hourly Parameter | Description | Obs | Fcst |
|---|---|---|---|
| Temperature | The air temperature. | √ | √ |
| Dew Point | The air temperature at which the air will become saturated, and dew moisture will condense into fog (or dew). | √ | √ |
| Relative Humidity | The amount of water vapor in the air compared to how much it could hold at this temperature (percentage). | √ | √ |
| Heat Index | The combination of air temperature and relative humidity determining a perceived air temperature. | √ | √ |
| Wind Chill | The combination of air temperature and wind speed determining a perceived air temperature. | √ | √ |
| Feels Like | The feels like temperature combines the heat index and wind chill into a single temperature value. | √ | √ |
| Wind Direction | The direction the wind is coming from, rounded to the nearest 10 degrees of compass heading. | √ | √ |
| Wind Speed | The sustained speed of the wind as measured at 10m (33ft) for official airport locations, or at 2.5m (7ft) for unofficial and agricultural locations. | √ | √ |
| Wind Gusts | The speed of wind gusts (if reported, this is the peak instantaneous wind speed observed in the 10 minutes prior to the observation). | √ | √ |
| Peak Wind Speed | The speed of the sustained peak wind | √ | |
| Wet Bulb Temp | The lowest temperature that can be reached by the evaporation of water only. | √ | √ |
| Minutes of Sunshine | The number of minutes of sunshine observed. | √ | √ |
| Solar Radiation | The Global Horizontal Irradiance (GHI) in Watts/m2. | √ | √ |
| Precipitation amount | Total of rain, ice, or snowfall. | √ | √ |
| Precipitation Type | The type of precipitation (rain, ice or snow). | √ | √ |
| Probability of Precipitation | The probability of any kind of precipitation to occur. | √ | |
| Weather Description | The general weather condition. | √ | √ |
| Sea Level Pressure | The atmospheric pressure reduced to mean sea level. | √ | √ |
| Visibility | Distance visible without instrumental assistance. | √ | √ |
| Observed Time | The time of observation. | √ |
Hourly Gridded Precipitation
This request returns Hourly Gridded Precipitation values for a particular location.
Multiple units of measure are available. Refer to the XSD at (http://weather.dtn.com/rest-3.4/doc/TDTNWeatherDataService.xsd) for valid values. Daily parameters are valid for a given location and a specified local calendar day; that is midnight to 11:59pm local time.
| Parameter | Description |
|---|---|
| Precipitation amount | Total of rain or ice, or liquid equivalent of snowfall. |
| Precipitation Amount List | A list of precipitation amount values in hourly increments dependent on timeframe requested. |
Aviation
This section includes three types of data returned for Aviation related measures. “Latest METAR”, “Latest TAF” and “Latest NOTAM”. Each is described in more detail in the following sub-headings.
Latest METAR
This request will return the latest (non-NIL) METAR for the requested location. You have the ability to omit the Station code and submit Lat/Long parameters to receive the nearest METAR to the coordinates. If no METAR is available for the last 2 hours for the requested position there are 2 options that can be specified:
Mode 1: The nearest station will be reported within a 100NM radius.
Mode 2: A message will be returned indicating that is no valid METAR for the required station.
The response contains the raw METAR observation text as well as a section containing the decoded METAR observation details as described in the following table. Refer to the XSD at (http://weather.dtn.com/rest-3.4/doc/TDTNWeatherDataService.xsd) for valid values and formats.
| METAR Parameter | Description |
|---|---|
| Time Position | Indicates the time of the METAR observation |
| Air Pressure | Indicates the current altimeter settings in hPa (hectopascal) |
| Air Temperature | Indicates observed surface temperature in Celcius |
| Dewpoint Temperature | Indicates observed surface dewpoint in Celcius |
| Horizontal Visibility | Indicates the minimum horizontal visibility in SM (statue miles) |
| Wind Speed | Indicates the observed surface winds in kts (Knots) |
| Wind Direction | Indicates the observed surface wind direction in degrees |
| Cloud Condition | Indicates the observed cloud cover at the station. Please note that BKN or OVC indicate a cloud ceiling |
| Cavok | True or False to indicate if Ceiling An Visibility OK or not |
Latest TAF
This request will return the latest TAF for the requested location. You have the ability to omit the Station code and submit Lat/Long parameters to receive the nearest TAF to the coordinates. If no TAF is available for the last 18 hours for the requested position there are 2 options that can be specified:
-
- Mode 1: The nearest station will be reported within a 100NM radius.
- Mode 2: A message will be returned indicating that there is no valid METAR for the required station.
The response contains the raw TAF forecast text as well as a section containing the decoded TAF forecast details as described in the following table.
Refer to the XSD at (http://weather.dtn.com/rest-3.4/doc/TDTNWeatherDataService.xsd) for valid values and formats.
| TAF Parameter | Description |
|---|---|
| Time Period | Indicates time of the particular forecast |
| Wind Direction | Indicates the forecast surface wind direction in degrees |
| Horizontal Visibility | Indicates the forecast minimum horizontal visibility in SM (statue miles) |
| Wind Speed | Indicates the forecast surface winds in kts (Knots) |
| Cloud Condition | Cloud condition forecasts at different elevations |
Latest NOTAM
This request will return the latest NOTAMs for the requested location. The ones returned will be ALL non-expired NOTAMs including the not yet active ones. Unlike METAR and TAF requests, NOTAMs are only returned for the station requested. If no NOTAMs are available, a message will be returned indicating that is no NOTAMs for the required station.
Values returned will include:
-
- Time period: Begin & End time for the particular NOTAM.
- NOTAM raw text