[stouset]

Sunburn has nothing to do with temperature. You can get a third-degree sunburn in sub-freezing temperatures.

[Kroniker]

It has to do with UV-irritation, I believe. This guy might be talking about getting burned by the sun, perhaps by being too close ;)

[semi-extrinsic]

Sunburn is inflammation of the skin. Inflammation is typically treated by cooling (e.g. when you put ice on a sprained ankle).