Weather conditions during December and January are one of the cloudiest in Canada outside of Newfoundland due to persistent valley cloud. As Okanagan Lake hardly ever freezes, warmer air rising from the lake climbs above colder atmospheric air, creating a temperature inversion which can cause the valley to be socked in by cloud. The last time the lake completely froze over was in the winter of 1969. It may have frozen over in the winter of 1986.Strachan, Brady, "It could be a lot colder: Kelowna historian remembers Okanagan Lake freezing over completely", CBC British Columbia, Retrieved on 2018-04-19. This valley cloud has a low ceiling, however, and often bright sunshine can be experienced by driving only 20 minutes or so up into the nearby mountains, above the cloud. Summers in Kelowna are very warm (sometimes hot) and sunny, with daytime temperatures often exceeding . Not unusually, heat waves occur in July, August, and even June and September on occasion, where temperatures above persist for weeks. Temperatures usually reach the high 30's °C or above for at least a few days each summer. The hottest temperature ever recorded in Kelowna was on June 29, 2021. During summer, clear, dry air allows night-time temperatures to fall rapidly, however nights are somewhat warm by Canadian standards. The city averages about of precipitation per year, with about a fifth of the precipitation falling as snow, the bulk in December and January; however, June is the wettest month of the year.
