Weather Conditions for various tracks:

Santa Anita
Hollywood Park
Del Mar
Fairplex
Bay Meadows
Golden Gate
Los Alamitos

Aqueduct

Arlington Park

Churchill Downs
Keeneland

Gulfstream

Hoosier Park

Laurel Park
LoneStar Park
Lousiana Downs
Meadowlands
Monmoth
Oaklawn

For a full list of North American tracks click here and go to "All North American Tracks:
All websites, weather info, addresses for all tracks" and press on the link