1. If it thunders on All Fool's Day, it brings good crops of corn and hay.
2. A cold May and a windy April, a full barn.
3. The louder the frog, the more the rain.
4. If the oak is out before the ash then we are in for a splash, But if the ash is out before the oak we are in for a soak.
5. March'll search ye, April try ye; May'll tell, whether live or die ye.
6. Rain before seven, fine before eleven.
7. Sounds traveling far and wide, A rainy day will betide.
8. A cow with its tail to the west, makes weather the best; A cow with its tail to the east, makes weather the least.
And then the one we all know:
April Showers Make May flowers.