San Francisco weather was made notorious by Mark Twain in his quote “the coldest winter I ever spent was that summer I spent in San Francisco”. The reputation is both deserved and terribly unfair.

The weather in San Francisco, California is never terrible. Huricanes and Tornadoes are unheard of in San Francisco. Thunderstorms are rare. Snow is would be a once in a life time event. Heat waves are short lived. Hot muggy weather is unexperienced. It does not rain in San Francisco, nor in the San Francisco Bay area from May through September. You can plan an outdoor activity without worrying about rain. And in the midst of any foggy morning there always seems to be the chance that the fog will burn off and produce a gloriously suny day, whether it is winter or summer.

Rain

Rain	inches	cm
January	4.06	10.3
February	2.95	7.4
March	3.07	7.8
April	1.29	3.3
May	0.25	0.6
June	0.15	0.4
July	0.04	0.1
August	0.07	0.2
September	0.26	0.7
October	1.25	3.2
November	3.21	8.2
December	3.10	7.9

As mentioned above it does not rain in San Francisco in the Summer, not enough worth talking about anyway. When my wife first visited Central California in the Summer she work up to a gray day and assume it would rain, but that was just a marine layer of fog that keeps the city from getting either too hot or too cold.

Temperature (when to visit San Francisco)

Days may be cool and foggy any time of the year and as Mark Twain discovered the warmest / sunniest days are not in the Summer. Any school student in Northern California can tell you that some of the nicest weather happens just after kids go back to school in September. Nights are always cool and there is no time of the year when you should come to San Francisco without a jacket. The sale of sweatshirts is as brisk as the temperature when the fog rolls over the tourists at Fisherman’s wharf. In the Summertime a short drive (1-2 hours) from San Francisco away from the ocean can easily see a rise in temperature or 10-30 degrees. The ocean keeps San Francisco cool to comfortable while people in Sacremento and the central valley bake.

High Temp	F	C
January	57	14
February	61	16
March	62	17
April	63	17
May	65	18
June	68	20
July	69	21
August	70	21
September	73	23
October	70	21
November	63	17
December	57	14
Low Temp	F	C
January	44	7
February	48	9
March	48	9
April	49	9
May	51	11
June	53	12
July	55	13
August	56	13
September	56	13
October	54	12
November	50	10
December	45	7

Sunshine

No month is San Francisco is filled with sunny days just as no month is devoid of them. One thing that the temperature statistics don’t say is that sunshine is not evenly spread throughout the city. The north and western parts of the city see more fog. I had two co-workers who lived on agacent hills in San Francisco. One hill, the one closest to the ocean, had fog almost every night, the other hill hardly ever had fog.

Sunshine	%
January	56
February	62
March	69
April	74
May	72
June	73
July	66
August	66
September	72
October	71
November	62
December	45