Taking into account the local weather in Garnavillo is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually July and August with an average temp of 69°F, while the coldest months are January and February with an average of 25°F. The snowiest months in Garnavillo are January, March, December, and February, with each month seeing an average of 7 inches of snowfall.