Taking into account the local weather in Deka Lake 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 58°F, while the coldest months are February and December with an average of 22°F. The snowiest months in Deka Lake are January, February, March, and December, with each month seeing an average of 17 inches of snowfall.