Weather will likely play an important role when you plan your trip to La Merced, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually September and October, with an average temperature of 21°C, while the coldest months are July and August, with an average of 20°C. The rainiest months in La Merced are February, January, December and March, with each month seeing an average of 342 mm of rainfall.