UTC Timezone Offset Error



This is more of a bug report than a problem.

I've been pulling information for both MTS and PSM TMY files for a handful of overlapping locations. However, there seems to be an error for the utc={"true","false"} flag.

When I set utc="true", the MTS TMY file seems to be at local time while the PSM TMY file is at the correct UTC time
When I set utc="false", the MTS TMY file seems to be offset the wrong direction, while the PSM TMY file is at the correct local time

Is this the expected behavior or is there something fishy with the timezone offset flags used? For now I'm just using local timezone files with utc="true" for the MTS data and utc="false" for the PSM data.

I've tested this at the TMY stations closest to the 7 SURFRAD sites.


Dear Andrew,

We are investigating this but in the mean time could you please send the exact coordinates for the PSM and MTS datasets, you are looking for. I checked  one pixel which is outside of the SURFRAD locations and it appears correct.

Please call or email if you have question.


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





I reported this also on 9/30/2016. It looks like the MTS1 database is still not fixed - it's still on the list in the viewer but not available when you go to download. We still need it because it is the only one that had the meteorological data such as cloud index, precipitation, and wind speed in addition to the solar radiation, and we need this for building energy simulation, specifically resilience studies and moisture risk studies. I was directed to the older data posting but that has only the solar radiation data. It was a great advance in the new NSRDB to get a full set of coincident historical meteo data along with the solar. It is frustrating that this time zone bug is holding up access to MTS1.