WSB, that looks like a good weather website. I'll bet they are pulling their information from the NOAA site we use on the Mt Whitney Weather page (link is in the Feature Topics box above on the left.)
The curious thing about the NOAA site, though: If you plug in the Lat/Lon coordinates for Mt. Whitney on the NOAA site, it returns with an elevation of 12162 ft, and temps that correspond closely with the temps on the "Climbing Weather" page. I have tried contacting NOAA people in regards to the elevation problem, but have never received even a single response.
We played with the NOAA site locations, and by changing the coordinates slightly, got it to give us an elevation of 13107 ft. Closer to the actual 14505, but still 1400 ft low!