The Timeline Weather API includes elements that are designed for use by the solar and wind energy industries. These weather elements include measurements of the solar radiation at the earth’s surface and wind speeds and directions.
The elements on this page are available only to certain subscription levels. For more information, please see our pricing page.
Extended wind speed and direction elements
The base Timeline Weather API offers windspeed and wind direction information at height 10 meters, the standard height for measuring and predicting wind information. The extended energy elements offer additional wind speed and wind direction information at 50, 80, and 100-meter heights. Wind speeds are returned in miles per hour, kilometers per hour, or meters per second, based on your unit group parameter. Wind directions are measured in degrees and based on the direction that the wind is blowing from (e.g. 0 degrees represents a wind blowing from the north).
When aggregated to days, hourly extended wind speeds indicate the average (mean) of the hourly values.
windspeed50 – the wind speed at height 50 meters.
winddir50 – the wind direction at height 50 meters.
windspeed80 – the wind speed at height 80 meters.
winddir80 – the wind direction at height 80 meters.
windspeed100 – the wind speed at height 100 meters.
winddir100 – the wind direction at height 100 meters.
Extended wind elements are currently available for forecast and and history since January 1st 2015 on an hourly basis.
Requesting extended wind elements using the Weather API
To request extended wind elements from the Weather API, include the values in the ‘elements’ parameter of the request. You can combine the extended wind 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,windspeed50,winddir50,windspeed80,winddir80,windspeed100,winddir100
Extended solar radiation elements
The extended solar elements extend the hourly solarradiation and solarenergy elements of the standard Timeline Weather API and include direct normal radiation, diffuse normal radiation, global horizontal radiation, global tilt radiation, and sun angle. Solar radiation measurements are returned in Watts/meter squared. In most cases. the values returned represent the average value for the preceding hour.
dniradiation – the direct normal radiation which is the sum of the beam radiation for the visible and infrared spectrums.
difradiation – the diffuse normal radiation is the sum of the diffuse radiation for the visible and infrared spectrums.
ghiradiation – the global horizontal radiation represents the solar radiation hitting a surface lying horizontally on the ground. It is the sum of the direct and diffuse radiation based on the sunelevation where ghiradiation = diffuse + direct * cos(sunelevation).
gtiradiation – the global tilt radiation for a surface tilted by an angle specified by the ‘solarTiltAngle’ parameter. It is calculated as gtiradiation = diffuse + direct * cos(sunelevation – solartitleangle).
sunelevation – The angle of the sun above the horizon in degrees. For hourly values, this is calculated at the mid-point of the hour. Daily values are the maximum value of this angle. The sun elevation angle can be converted to the solar zenith angle using zenith angle= 90 – sunelevation .
Extended solar elements are currently available for forecast and history since January 1st 2015 on an hourly basis.
Requesting extended solar radiation elements using the Weather API
To request extended solar radiation elements from the Weather API, include the values in the ‘elements’ parameter of the request. You can combine the extended solar radiation elements with other weather elements such as the following example that includes temperature. In addition, do not forget to include the solarTiltAngle parameter to specify the angle in degrees.
https://weather.visualcrossing.com/VisualCrossingWebServices/rest/services/timeline/Denver,CO?unitGroup=metric&key=YOUR_API_KEY&contentType=csv&elements=datetime,ghiradiation,dniradiation,difradiation,gtiradiation,sunazimuth,sunelevation&solarTiltAngle=45
Questions or need help?
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