Taking into account the local weather in Mielnik is an important factor for planning your visit, especially if you plan to spend your trip poolside. The hottest months are usually August and July with an average temp of 64°F, while the coldest months are January and February with an average of 31°F. The snowiest months in Mielnik are January, December, November, and February, with each month seeing an average of 12 inches of snowfall.