Is coastal California’s weather really “that nice” in the summer?

By CBS Bay Area

While the rest of the country is baking in extreme heat, the Bay Area is feeling nice and comfortable, and recently, somebody asked, ‘Is the weather really that nice in California?’ 

The central and southern coasts of California have what is known as a Mediterranean climate, which occurs on the west coasts of all continents in the mid-latitudes, but only accounts for about 2% of all land on Earth. This is the only Mediterranean climate in North America. 

There are only four other places on Earth that have this climate: the Mediterranean Sea, Central Chile, the western Cape of South Africa, and western and southern Australia. These climates have mild, wet winters and warm, dry summers. The summer sun is strong during the day, but a chill takes hold once the sun sets and the sea breeze ramps up. Sound familiar? 

Here in the Bay Area, it all revolves around microclimates. The mountains and valleys along the coast allow temperatures to range 20 degrees in only a 20-minute drive. Coastal mountains trap all the fog directly along the coast while also stopping the fog from moving inland. It’s the gaps in our coastal mountains that allow the marine layer to fill farther inland and act as a natural air conditioner across the Bay Area, which is the reason it’s cooler than in the Central Valley.  

The average precipitation for the entire summer total is around 0.25″, mainly falling as mist/drizzle. San Francisco’s average summer high temperature is 67°, Oakland is 72°, Santa Cruz is 75°, San Jose is 80°, Napa is 83°, and Livermore is 86°.  

Out of all major cities in the continental U.S., San Francisco averages the coldest summertime temperatures. Comparing San Francisco to the rest of the country, Seattle has the most similar temperatures, an average of 75° through June, July, and August, thanks to it being on the West Coast as well, but it doesn’t deal with nearly as thick a marine layer, so temperatures get slightly warmer. The downside of Seattle is that there’s a much better chance of getting rained on than in San Francisco in the summer. Los Angeles is nice, but nearly 10 degrees warmer than our average summer temperature, although rain chances are lower.

The summertime heat really cranks up in the south, with Phoenix’s average temperature of 105°; surprisingly, Arizona on average sees more total rainfall in the summer than most of coastal California. Dallas is also hot, not as hot with average highs in the mid-90s, but there is way more rain. When there is rain and moisture, there’s humidity, which sometimes makes it feel even hotter and more unbearable in Texas than in Phoenix, even when the temperature is technically cooler. 

Denver isn’t as hot as Dallas, in the mid-80s, but it’s hotter than Chicago on average during the summer. However, when planning a summer vacation, Chicago normally sees more than double the amount of total rainfall Denver sees during the summer months. 

And fun fact — New York City is one of the wettest big cities in the country during the summer, averaging over a foot of total rain!

So, for people who like a comfortable heat, a sea breeze with some fog, along with little to no rain to worry about, California is really “that nice” in the summer.