If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Chapala: The hottest months are usually May and April with an average temp of 74°F, while the coldest months are January and December with an average of 65°F. The rainiest months in Chapala are July, August, September, and June, with each month seeing an average of 7 inches of rainfall.