California doesn't have typical seasons throughout the state. Go to one area and you may need a jacket while in another part of the state, you may be sunbathing in a swimsuit. However, the weather is somewhat predictable in each region. You will have more fun visiting an area if you know what to expect.
Areas along the coast are temperate year-round. Visit the northern portion of the coast and you will enjoy mild temperatures. This includes San Francisco where summertime temperatures are often no higher than 70 degrees Fahrenheit. With fog rolling in off the water, it is often cool in the early mornings and evenings even in July and August. Winter can be quite chilling, but don't expect snow.
Farther south and you will notice more rain, but mild temperatures throughout the year. It does get warmer though and mornings and evenings are not quite as cool.
Locals take to the mountains in the summer to cool off, especially those who live around the desert. It is a great place to go hiking or spend time outside with other activities because they temperatures are not as intense. They go back in the winter to enjoy snow and activities such as skiing and snowboarding. Expect snow from December through March around Lake Tahoe and other popular areas
Southern California and the Desert
Expect warm weather even in the winter and hot temperatures in the summer around Los Angeles and other areas. Along the coastline, you will enjoy comfortable temperatures, but move inland and it begins to heat up. Expect to see temperatures in the 50's and 60's during the winter, which is perfect for outdoor activities.
If you want to visit the deserts, avoid the heat of summer when temperatures are often at 100 degrees or higher. Winter is the perfect time to spend time in this area with more moderate temperatures. Don't forget to pack a jacket since the nights can get quite cool.
While you can't generalize on the temperatures of California, you can expect the coastline to be more moderate than inland. As you travel farther away from the coast, expect to see an increase of about one degree per mile. For instance, the average temperature in July around San Francisco is 72 degrees, but just 20 miles away in Walnut Creek the average goes up to 90 degrees during the same time.
Because of this disparity in temperatures, you want to know where you are going and what to pack. While California is considered a temperate climate, it means different things depending on where you plan to spend your time.