If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Ahuachapan: The hottest months are usually March and April, with an average temperature of 25°C, while the coldest months are January and December, with an average of 23°C. The rainiest months in Ahuachapan are September, June, May and October, with each month seeing an average of 325 mm of rainfall.