Tijuana's climate is semi-arid (K�ppen climate classification BSh), with about 231 mm (9.09 in) of annual precipitation. It shows characteristics of the Dry-Summer Subtropical Mediterranean climate (Csa) found to the immediate north, with most of the annual precipitation falling in the winter (between November and March).
During the rainy season, November through March, storms originate from fronts entering off of the Pacific Ocean. January is the wettest month of the year for the city and during this time a periodic event, similar to June Gloom, is observed created by marine layer. January is the coolest month, during which temperatures average 13� Celsius. In the city April signifies the end of winter and the start of Santa Ana winds - observed in Southern California as well. Though the days are predominantly cool with cold nights, heat waves can reach up to 33� Celsius. The hottest months in the city, also the dry season, are August and September, during which temperatures average 22� Celsius.
Frost and snow are rare phenomena in the city as temperatures are usually warm. Yet, in December 1967, snow fell in the city and in January 2007 feather light snow fell in the east of the city. However, excessive amounts of snow fall have never been recorded in the city. On February 14, 2008 a winter storm caused an unusual snowfall in the upper reaches of the hills of the city. During this time heavy snowfall was also observed in the Cuyamaca Mountains of San Diego County.
The record low temperature recorded in the city was -6� Celsius, while the highest was 42� Celsius
