ok, I take up this challenge with aplomb. I found Les' list a tad literal. Janis' Summertime always sounds wintry to me.

Summer:
Steal my Sunshine - Len
Hot Fun in the Summertime - Sly and the Family Stone
Long Hot Summer Night - Jimi Hendrix Experience

Rainy Day:
Rainy Day, Dream Away - Jimi Hendrix Experience
Riders on the Storm - Doors
The Rain Song - Led Zeppelin

Mike