Weather will likely play an important role when you plan your trip to Osorno, but bear in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually January and February, with an average temperature of 15°C, while the coldest months are July and August, with an average of 7°C. The rainiest months in Osorno are August, June, July and May, with each month seeing an average of 237 mm of rainfall.