PSM 30min data files


Do the DNI, GHI, and DHI data in the downloaded PSM files represent mean W/m^2 values over a 30-min interval? If so, is the mean taken over the preceding interval or the following interval? For example, if a value is reported for 10:30am, is it an average taken over the 10:00-10:30am interval or the 10:30-11:00am interval? Or, is it an instantaneous value taken exactly at 10:30am? Also, I assume that the recorded local clock times do not use Daylight Savings Time - is this correct? Thanks!


The irradiance values in the NSRDB-PSM model grid represent an instant in time rather than an integrated value.

- Yes there is no daylight savings time.


Aron Habte


Sensing, Measurement, and Forecasting Group

Power Systems Engineering Center

National Renewable Energy Laboratory (M/S SRRL)

15013 Denver West Parkway , Golden, CO 80401
Office: 303-384-6389 | Lab:303-384-6326 | Fax:303-384-6391