If that isn't an oxymoron. But you know what I mean.

I was probably a little slow at a recent race just because it was the warmest day of the year so far. The week before was more mild so it's a bit of a lottery. No big deal. A friend just struggled in a big city destination marathon and was quite a bit slower than normal which they put down to it being warmer than expected.

It seems to me that in spring you often don't know when it will start getting hot and, because you are coming out of winter, you won't be adapted to it. I think a week or two adaptation is recommended but I don't really trust a weather forecast a week out. Certainly it was wrong for my recent run a week out. These aren't hot temperatures in the big scale of things. Once it's summer we probably wouldn't even think about the same temp. So, for me, it's a spring specific question.

My guess is if you have a spring A race there is an argument for acclimatising to heat just in case. But does anyone actually do that? Is there a down side to doing that and then getting a colder day? Maybe you could start about 10 days out and then just stop if 3 or 4 days out the forecast is mild? Just interested in what people do.