Osorno has an oceanic climate (Köppen climate classification Cfb) with a drying trend in summer. Winters are cool but mild with a July average of . Most of the precipitation falls during this time of the year with May to July being the wettest months, averaging around to of precipitation and humidity is high, averaging around 85%. Snowfalls are rare. Summers are drier and mild with a January average of and during this time, precipitation is lower, averaging in January. In some years, many days can go without a day of precipitation such as the case in 1992 when only of precipitation was recorded in January while in other years, some summers can have several wet days in a row. Temperatures can occasionally exceed anytime from December to March. The average annual precipitation is and there are 173 days with measureable precipitation. The record high was in February 2019 and the record low was in July 1954.