Planning for the weather is a good way to make your trip to Ossona relaxing and enjoyable, especially when you’re splurging. The hottest months are usually July and August with an average temp of 71°F, while the coldest months are January and December with an average of 41°F. The rainiest months in Ossona are November, October, May, and August, with each month seeing an average of 8 inches of rainfall.