If you’re hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Los Alamos: The hottest months are usually July and June with an average temp of 68°F, while the coldest months are January and December with an average of 32°F. The snowiest months in Los Alamos are March, January, December, and February, with each month seeing an average of 9 inches of snowfall.