Weather - A Local's Guide For Visiting Or Moving To San Francisco

"The coldest winter I ever spent was a summer in San Francisco"
- (Not by) Mark Twain

The Contest

Maybe this is a local urban legend, but I have heard that groups of friends make bets around spring and summer of each year. It's sort of like a bird-watching contest.

The bet is on which of them will be the first to spot the first tourist of the year, wearing a Hawaiian shirt, shorts, white socks and conservative shoes, holding an SF map and shivering in the windy fog on Market Street.

The winner is said to have spotted the first Mapping Tourist sporting a Full Minnesota outfit.

Micro-climates

It's a well-known fact of life to us that San Francisco neighborhoods are all micro-climates. Our TV stations brag about their weatherpeople, who are touted as "micro-climate experts".

You can be in fogged-in winter in the Sunset, go to the other side of the city and be in sunny summer California in the Mission. Wear a bikini under your parka.

Winter

Temps you're likely to encounter :

Coldest night : About 28 F
Warmest day : About 55 F

It's wet, but it's a wimpy wet. We rarely get strong showers, it's more like something between heavy mist and soft rain. Temps reach highs in the 50s. Half the time, it's actually sunny, cold, and crsytal-clear with not a cloud in the sky. Gorgeous walking weather.

I have a heavy parka for cold, heavy rain which I only wear a handful of times a year. The rest of the rainy season, a light, impermeable parka will do. I stuff a sweater in my backpack in case it gets cold, or nightfall catches me outside.

Spring

Temps you're likely to encounter :

Coldest night : About 45 F
Warmest day : About 80 F

Early spring is often overcast; late spring is often sunny but not hot. Actually, it's unpredictable, depends on the whim of the weather gods and in the neighborhood where you are.

Dress for a mildly warm spring day, be prepared to shed something if the sun starts to beat down, or if dusk catches you outside, to put on a sweater. Temps in the 60s and 70s. The last rain is sometime in March or April

Summer

Temps you're likely to encounter :

Coldest night : About 50 F
Warmest day : About 90 F

It's foggy, and more often than you would think, especially in the western third of the city. That combination of cold water and warm air socks us in, and that is usually when the tourists can be seen shivering around the cable-car turnaround. Remember, this depends on the micro-climate in which you find yourself.

It's seldom thick London fog, just low cloud thin fog. It usually clears by 11 or noon, unless you are in the Sunset, parts of which are known for having their fog clear last.

Fall

Temps you're likely to encounter :

Coldest night : About 40 F
Warmest day : About 100 F

Very warm, sometimes hot around "Indian Summer". We only get two or three days that reach temperatures above 100, and they are usually in September or October (sometimes November). This is a great time to come, all the tourists are gone and that's when real summer-like weather hits. Ssshhhhh, let's keep it between us.