Back when I was in college I read some paper by some sheriff in Louisiana. The sheriff had analyzed riots like Watts, Homestead and many more. What flash point kicked off the riots? Was it lack of food? Someone wrongly charged? No, it was temperature. The sheriff claimed that the most common flash point is 92 degrees. Hotter than than, it's too hot for people to go around rioting. Colder and people seem more docile. But, when the mercury hits 92, watch out.
Now, I don't know if people are going to start as the weather gets warmer, but there's a lot of tension in the air. People can only stay clamped down for so long. And I've never tested the sheriff's theory, but it's getting warmer every day.