The Timeline Weather API includes elements that are designed for use by the agricultural, farming and horticultural industries. These elements are designed to providing weather data that influence those who grow plants or raise livestock.
The elements on this page are available only to certain subscription levels. For more information, please see our pricing page.
Degree days
The Timeline Weather API provides degree day calculations for all historical and forecast periods.
For full information on including current and accumulated degree values into the Timeline API response, please see our Degree Days Weather API article.
Soil temperatures
The API provides four depths of soil temperatures: 0-0.1m, 0.1-0.4m, 0.4m-1.0m and 1.0-2.0m. Each soil temperature is calculated at the hourly level. Daily values are the average (mean) of the hourly values. The temperature is returned in Celsius, Fahrenheit or Kelvin based on your ‘unitGroup’ parameter.
soiltemp01 – the soil temperature for depth 0-0.1m.
soiltemp04 – the soil temperature for depth 0.1-0.4m.
soiltemp10 – the soil temperature for depth 0.4-1.0m.
soiltemp20 – the soil temperature for depth 1.0-2.0m.
Soil temperatures are currently available for forecast and history since April 1st 2022 on an hourly basis. . Please contact Technical Support for more information on the availability of older historical soil temperatures.
Requesting soil temperatures using the Weather API
To request soil temperatures from the Weather API, include the values in the ‘elements’ parameter of the request. You can combine the soil temperature elements with other weather elements such as the following example that includes temperature.
https://weather.visualcrossing.com/VisualCrossingWebServices/rest/services/timeline/Denver,CO?unitGroup=metric&key=YOUR_API_KEY&contentType=csv&include=days&elements=datetime,temp,soiltemp01,soiltemp04,soiltemp10,soiltemp20
Soil moisture
Soil moisture levels are available for the same depth levels as soil temperature: 0-0.1m, 0.1-0.4m, 0.4m-1.0m and 1.0-2.0m. There are two forms of soil moisture elements – soil moisture content which provides the amount of water in inches or mm (depending on your unit group) or as a soil moisture content as volumetric fraction ranging from 0 to 1.
soilmoisture01 – the soil moisture for depth 0-0.1m
soilmoisture04 – the soil moisture for depth 0.1-0.4m.
soilmoisture10 – the soil moisture for depth 0.4-1.0m.
soilmoisture20 – the soil moisture for depth 1.0-2.0m.
soilmoisturevol01 – the soil volumetric moisture for depth 0-0.1m
soilmoisturevol04 – the soil volumetric moisture for depth 0.1-0.4m.
soilmoisturevol10 – the soil volumetric moisture for depth 0.4-1.0m.
soilmoisturevol20 – the soil volumetric moisture for depth 1.0-2.0m.
Soil moistures are currently available for forecast only and history since April 1st 2022 on an hourly basis. . Please contact Technical Support for more information on the availability of older historical soil moisture elements.
Requesting soil moisture using the Weather API
https://weather.visualcrossing.com/VisualCrossingWebServices/rest/services/timeline/Denver,CO?unitGroup=metric&key=YOUR_API_KEY&contentType=csv&include=days&elements=datetime,soilmoisture01,soilmoisture04,soilmoisture10,soilmoisture20,soilmoisturevol01,soilmoisturevol04,soilmoisturevol10,soilmoisturevol20
Evapotranspiration
et0 – reference evapotranspiration et0
Evapotranspiration provides a measurement of the amount of moisture that will be evaporated or transpired from a given location based on the weather conditions. This value is calculated using the Penman–Monteith method which incorporates the solar radiation, air temperature, air humidity, and wind speed to calculate the estimated value of evapotranspiration. The value is calculated on an hourly basis and is the aggregated (via a sum) to provide daily estimates. The evapotranspiration values are specified in mm or inches based on your unit group selection.
Evapotranspiration is available for forecast and historical hours and days.
Requesting evapotranspiration using the Weather API
https://weather.visualcrossing.com/VisualCrossingWebServices/rest/services/timeline/Denver,CO?unitGroup=metric&key=YOUR_API_KEY&contentType=csv&include=days&elements=datetime,et0
Wet bulb and deltaT
The web bulb temperature is an optional element that indicates the level of water vapor in the air, similar to the humidity element. A wet bulb temperature near the air temperature indicates a high amount of water vapor. If the web bulb temperature and air temperature are the same, the air is saturated (and the relative humidity will be 100%).
The deltaT element provides the difference between the dry bulb and wet bulb temperature.
Both wet bulb temperature and deltaT use the same temperature unit as the air temperature, depending on the selected unit group.
Requesting wet bulb and deltaT elements using the Weather API:
https://weather.visualcrossing.com/VisualCrossingWebServices/rest/services/timeline/Denver,CO?unitGroup=metric&key=YOUR_API_KEY&contentType=csv&include=days&elements=datetime,temp,tempwet,deltat
Questions or need help?
If you have a question or need help, please post on our actively monitored forum for the fastest replies. You can also contact us via our support site or drop us an email at support@visualcrossing.com.