Taking into account the local weather in Westerpark 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 61°F, while the coldest months are January and February with an average of 38°F. The rainiest months in Westerpark are October, September, November, and December, with each month seeing an average of 9 inches of rainfall.