I have been in high -30Cs (or is it more correct so say low in this case?) in Lapland. I guess it was around -36 or -37?
I have also been in high 40s (46 or 47) in the Danakil Depression in Ethiopia, which also happens to be one of the lowest points on land on the planet. But we also hiked to the edge of a volcano and hot springs. I think it may have been even hotter there? but that would probably be cheating.