Weather will likely play an important role when you plan your trip to La Paz, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually August and May with an average temp of 80°F, while the coldest months are February and January with an average of 77°F. The rainiest months in La Paz are January, December, November, and May, with each month seeing an average of 13 inches of rainfall.