n the south end, tropical storms called chubascos can bring torrential rains and heavy winds from mid-May to mid-November, peaking in August and September, although abnormal water temperatures can cause exceptions. Most such storms affect only the state of Baja California Sur, the southern half of the peninsula, but they occasionally move up the Cortez to go ashore at San Felipe or into Sonora. Although varying greatly from year to year, the Cape region averages 8 inches to 16 inches of rain a year, and isolated areas in the mountains can get up to a distinctly nondesert 30 inches. For comparison, Seattle, famous for its rain, gets an average of just over 38 inches.
he relatively cool waters of the California Current keep air temperatures along Baja's Pacific coastal areas comfortable most of the year, but temperatures soar along the western coast of the Cortez during the summer. The area around Mexicali consistently experiences summer temperatures in the 104 to 108 degree range, occasionally getting up to 120 degrees, and on a windless summer day, Santa Rosalía can seem as hot as a blast from the town's copper smelters. The Cape region tends to have moderate temperatures all year. As in desert areas elsewhere, day-to-night temperature variations are extreme, and it is not uncommon for travelers to run the heaters of their vehicles early in the morning and their air conditioners in the afternoon.
espite its normally warm and dry weather, Baja occasionally provides a few surprises. Mountain areas can be very cold in winter: while traveling in the Sierra San Pedro Mártir in 1905, adventurer Arthur North was surprised to find that his canteen had frozen solid. These mountains can accumulate up to 8 feet of snow, and the Ensenada rescue squad has been called out a number of times to retrieve stranded hikers. Snow can occasionally fall at lower elevations; in 1987, 5 feet fell at the 4,200-foot level in the Sierra de Juárez.