If you’re hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Sayulita: The hottest months are usually May and June, with an average temperature of 26°C, while the coldest months are February and January, with an average of 22°C. The rainiest months in Sayulita are August, September, July and June, with each month seeing an average of 265 mm of rainfall.