The best time to travel California depends on your local destination.
To explore the coastline you should rather come here in spring or fall because there coastal fog is common along the shore from mid of June until the end of September.
California’s Central Valley is pleasant all year long. Most times it is sunny, mild and pleasant. The only exception is the summer with temperatures up to 100-110 degrees.
Going to the Sierra Nevada you have to reckon with heavy snowfall from November - April that most times is causing road closures. The rest of the year the weather is usually nice with moderate temperatures.
Surfers, Snowboarders and Skiers should travel to California from January to March. During that time they are catching the best low tides and swells in surf cities like Santa Cruz and best powder in the Sierra.
Beach lovers, who are thinking about beach vacations only, shouldn’t plan them in San Francisco! The water is freezing cold and the summers are chilly. There is no way of hitting Ocean Beach without a blanket or fleece - seriously. Instead plan your beach outing in SoCal.
HWY 1 Route Recommendations
When driving along HWY 1 to see the Big Sur coastline go from North to South since all vista points are at the ocean side.
HWY 1 is a common tourist route through California. To cover the most exiting sights start in San Francisco and end the trip in San Diego. Depending the length of your trip you can branch off to Las Vegas, Death Valley, Yosemite, and/or Lake Tahoe.