April showers bring forth May flowers

Aprell sylver showers so sweet Can make May flowers to sprynge.
[c 1560 in T. Wright Songs & Ballads (1860) 213]

April showers bring forth May flowers.
[1670 J. Ray English Proverbs 41]

March winds and April showers bring forth May flowers.
[1846 M. A. Denham Proverbs relating to Seasons, &c. 36]

If there was anybody left to believe in the saying that ‘April showers bring forth May flowers’ their simple faith must have been rudely shattered by May's behaviour this year.
[1921 Sphere 14 May 152]

If April showers bring May flowers, what do June brides bring?
[2001 Washington Post 1 July F1]

Related to: weather lore

Bibliography of major proverb collections and works cited from modern editions is available here.