Weighted Irradiance Data Download
Sunny and Cloudy Days
The final criteria for designating a day as sunny requires a mean 368 nm transmittance of 0.58 and a standard deviation of transmittance less than 0.10 throughout an interval on either side of solar noon that is within 0.6 of the half daytime length for the site. The algorithm has been evaluated as agreeing with continued scrutiny by our staff approximately 90% of the time.

Location and Time User Inputs

Time Duration