Does climate affect conflict? Evidence from Shakespeare

Mark Cane sends us this:

ROMEO and JULIET         ACT 3, SCENE 1a 

[A street. MERCUTIO, BENVOLIO & Servants] 

BENVOLIO
I pray thee, good Mercutio, let's retire.
The day is hot, the Capulets abroad,
And if we meet we shall not 'scape a brawl,
For now these hot days is the mad blood stirring.

[And later they do meet the Capulets and Tybalt kills Mercutio, then Romeo kills Tybalt and the rest is tragedy.]

For more fun evidence on the psychological effect of heat on aggression, see evidence from road rage and MLB.  Also this.