I think the whole thing of the longest day being the turnaround point of summer (and not in a good way) is very deeply ingrained in some of us. I'm in my house in Spain, the aircon's set to 25 (outside is closer to 30) and there's wall-to-wall blue sky, and I'm still feeling something like dread - "Oh, no, the longest day, the nights are drawing in and winter will be here soon."
I'm not trying to make anyone jealous, by the way, just saying how ridiculous it is that I'm somehow "programmed" to react like that.