Does the heat irritate people?

I wonder if the heat causes aggression. There were 18 murders in my city (Austin, Texas) one week last July. Austin had more killings last July than the other 11 months combined. Last year, over 100 homicides occurred in Houston during July and August. Fourth of July weekend was the worst. Several shootings and stabbings occurred then. A few took place around the corner from me. Lately, people have been really nasty. I don't if it's the weather or the full moon, but it was 97 degrees today. I wonder if it caused rectal itch or something? Does the heat make everyone spiteful?