solar cells now economic even in Norway!

Originally posted by @humy
https://phys.org/news/2018-03-solar-cells-nordic-climate.html

Didn't know about the 0.3% loss per degree up in temperature. How far down in temp does that hold? 30 degrees up, 3% loss but 30 degrees down, 3% gain? 60 degrees, 6 % gain? I assume that would be starting at room temp, say 20 degrees C, also are they talking C here or F? If that held going down then you would expect at -10 C efficiency would go up 3%. But which unit are they talking about, C or F.