We always used to have a week over there in May and found the pools to be freezing - mainly due to heat loss overnight (it is pretty cool at night in May), but also due to the fact that they probably aren't long filled so haven't seen much sun. Worse still, if it is filled using well water, that is almost ice cold when drawn

All that said, it never stopped us using them

When we lived there, we didn't even fill our pool till the end of June, and used to scoff at the silly tourists swimming
