I'd have to agree that the weather effects are more that they run more at night. This means they are bedded up more during the day if its warm....you get the occasional over achiever of course but the big boys probably lay low during the heat of the day ....think about all that running around they do. You know it wears them out in the heat....

Just think of it that way... makes sense doesn't it....I don't think the weather effects if they go in heat or not. But I could be wrong