Do you know the rhyme, 30 days have September, April, June and November? If you can't remember it then Oliver L told us about a way to figure out which months have 31 days and which have 30:
1. Count the months on your knuckles and the grooves between your knuckles.
2. Every month that lands on a knuckle is 31 days, every month that lands on a groove between knuckles is 30 days (or 28 for February).