Taking into account the local weather in Tambo Unión is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually September and October with an average temp of 66°F, while the coldest months are July and August with an average of 64°F. The rainiest months in Tambo Unión are April, May, June, and March, with each month seeing an average of 17 inches of rainfall.