I think its as simple as reaction to heat being relative to what you're used to. I was thinking about this earlier in the other "Sweden" thread because it routinely gets over 100F here in Texas during the summer. Yet we all complain a bit when it hits temps like 104 and then just go on. On the flip side of the coin I remember a swimming pool at a family reunion that I wouldn't touch because it was unreasonably cold. A cousin of mine from New England jumped right in and told me it was warmer than he was used to. I suppose our bodies just adapt to our environment.