I don't know if it's just me or it happens to others (I think I have heard the term "summer insomnia" before) but additionally to all you mentioned I will also say how much sleep I am personally loosing during the summer.

A typical night follows:

Lay down to sleep around 12:30, keep moving trying to cool off, sweating, the dogs are barking like mad and in combination with the wide open windows, they make me want to kill them all (terminator style). Around 2 and I am still wide awake! I have to desperately pee because I have consumed 3lt icy water. Around 2:30 I am finally dreaming (of you if I am lucky lol) but only until 4:30. That spooky feeling of a fucking κατσαρίδα walking on my chest wakes me up. Ewwww! I jump out the bed, turn on the lights and I kill every insect in sight with my παντόφλα, while I try to suck my blood back from these evil mosquitoes. An hour later I manage to fall asleep again, only to wake up 2-3 hours later if I am lucky. The sun is reigning 18 hours (minimum) during the summer in Greece, while the fucking noise outside and loud Greeks are x10 worst because of the freaking open windows.

Man!!! I hateeeeeee summers!!!