California

California Weather Overview

Sea, Sun, Surf- the three things that probably spring to mind when you hear the word California. While these are characteristics that can most certainly be attributed to California, it in fact has a whole lot more to offer than just beaches and celebrities. As you move around the state, which at 411, 000 square kilometers is the 3^rd largest US state, you can see a smorgasbord of climates- from Oceanic to Semi Arid, from arid to sub tropical, from arctic to Mediterranean. The cause of these climatic variations it due to the varied terrain across the state and the changing proximity to the Pacific Ocean.

California has a long coast adjacent to the Pacific Ocean, and it is this huge water mass that has such a large affect on the prevailing weather conditions in California. The Pacific carries the ‘California Current’ which is a cool ocean current that begins in the far north off the coast of Canada’s British Columbia, and continues right down the west coast of USA until you reach the Mexican state of Baja California. This current which brings cool waters down from the far north, makes the ocean waters much cooler than that of comparable latitudes on the East coast of the country.

The California Current also has the affect of creating summer fog which lies low throughout all of the California coastal cities. The fog, which has become known as ‘May Gray’ or ‘June Gloom’ causes when the wind from inland California moves westward and hits the cool ocean waters. This creates a thick dewy fog which is present in the western parts of the cities and often lasts throughout spring and a lot of summer. The dense cloud cover means that early mornings are particularly foggy and there can be occasional drizzle, also has the affect of keeping temperatures much lower at the start of summer than on the same latitude on the east coast or further inland.

Starting in the North of California you will find your self in the Napa Valley- which is a beautiful and famous wine making region that produces wines of the same standard as Italy and France. The Napa Valley is home to rolling green hills, picturesque never ending vineyards and countless wineries in which to keep your self busy. You have probably seen a picture of the Napa Valley without even realizing, as the standard Windows XP backdrop of a bright blue sky and lush green hill, is in fact an image taken in the Napa Valley. In the Napa Valley and the entirety of the Napa County conditions are fairly pleasant all year round. Summers can get hot, but not too hot.. and the barometer will generally sit somewhere in the high 20’s. Like most Mediterranean climates, which is the climate that prevails in Napa, the rain comes in the winter months- with December, January and February generally being the wettest months.

Moving further south and toward the coast you will reach the vibrant city of San Francisco, home to the Golden Gate bridge and an electric and exciting cultural life. San Francisco is one of the most densely populated cities in all of the US, though it by no means feels overcrowded when you are visiting and the city has a great homely feel to it. You can take your self from the steepest street in the world, head down it and explore the winding narrow streets before ending up at Fisherman’s Wharf and taking in the never ending buzz of activity that happens down at the wharf.

As San Francisco is surrounded on 3 sides by water it is strongly influenced by the cool currents of the Pacific, it is also subject to the Fogs which take over the sky in late spring. The hottest temperatures don’t really come until the end of summer, a result of the Californian current. June, July and August see maximum highs of 18 degrees and lows of 12 degrees, before warming up to highs of 21 degrees in September and 20 degrees in October. The highest temperature ever recorded in San Fran was 39 degrees, which occurred in June 2000.

Winter in San Francisco is mild and very very rarely sees snowfall- there have only been 10 instances of snowfall since 1852. December and January each see average daily highs of 13 degrees and lows of 7 or 8 degrees, while February (generally the wettest month) has average daily highs of 15 degrees and an average minimum of 8 degrees.

The varied topography across the city means that precipitation differs wildly from area to area. The high hills which lie in the centre of San Francisco cause a 20% annual variance in rainfall across the city. See here for rainfall in central San Francisco. You can also see further tables for temperature and sunshine.

Once you move inland the conditions begin to get more extreme, winters are colder and summers are hotter. As you move further south, the inland conditions become increasingly arid and verge on desert. Death Valley, which lies in south eastern California has a climate which is fairly indicative of its name! It gets deathly hot here, in fact it is the hottest spot in the western hemisphere, and in Death Valley it is common for temperatures to reach 49 degrees! The hottest temperature ever recorded in the western hemisphere occurred in Death Valley when the mercury hit an unimaginable 57 degrees Celcius, which happen on July 10 1913. More recently, 2005 saw temperatures hit above and over 54 degrees! Not a place to be taking in the outdoor surroundings in!

In the far south of California you will reach the city that combines glitz and glamour with a seedy tacky ambience, the city of Los Angeles. Conditions from Santa Barbara, north of LA and further down the coast to San Diego are much the same, though the temperatures do increase ever so slightly as you move further south toward to equator.

This area sees an enviable Mediterranean climate of hot summers that are tempered by sea breezes off the ocean, and mild winters which see most of the years annual rainfall.

See here for an overall look at the conditions in Los Angeles and here for San Diego.

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