Right now, San Francisco is doing that weird thing it does where the microclimates decide to play musical chairs. If you’re looking at the sky today, Sunday, January 18, it's mostly cloudy with a current temp sitting at 51°F. Honestly, it feels more like 46°F because of a steady 9 mph breeze coming off the North.
You’ve probably heard the old (misattributed) quote about the coldest winter being a summer in San Francisco. Well, January 2026 is proving that winter here isn't exactly a frozen tundra either, but it's definitely moody.
The Immediate Forecast: Sunday and Monday
Today, Sunday, we’re looking at a high of 59°F and a low of 49°F. It’s basically "light jacket" weather. The UV index is a low 2, so you won't be getting a tan at Dolores Park, but you won't need an umbrella either—there’s only a 10% chance of rain.
Tomorrow, Monday, January 19, things stay pretty consistent. We’re expecting broken clouds with a high of 61°F and a low of 47°F.
Wait, here is the kicker. While the city stays in the low 60s, the National Weather Service (NWS) has been tracking a major temperature inversion. This means the higher you go, the warmer it gets. Last Friday, people in the mountains were hitting the 70s while the valleys were shivering near freezing. We’re still seeing some of that "thermal belting" early this week.
Mid-Week Clarity vs. The Weekend Drip
Tuesday, January 20, looks like the winner for outdoor plans. It’s forecasted to be sunny with a high of 62°F. If you’re planning to walk the Golden Gate Bridge or head to Alcatraz, this is your window. The wind should drop to about 5 mph, making the bay air feel way less bitey.
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The Breakdown for the Rest of the Week:
- Wednesday (Jan 21): Broken clouds return. High of 61°F, low of 49°F.
- Thursday (Jan 22): It gets a bit gloomier. Overcast skies with a high of 58°F.
- Friday (Jan 23): Back to sunshine. High of 59°F.
Basically, the first five days of this week are dry. But don't get too comfortable. The NWS and long-range models from Almanac.com suggest a weak short-wave trough is moving in by Friday night. This could bring light rainfall into Saturday.
What to Actually Pack
Forget the heavy parka. You’ll look like a tourist and you’ll be sweating by noon. San Francisco weather this week is all about the "SF Uniform."
You need a base layer (t-shirt), a solid mid-layer (hoodie or wool sweater), and a wind-resistant shell. Since the humidity is hovering around 81% right now, the cold feels "damp." It gets into your bones more than a dry cold does.
The Fog Factor
Fog is the permanent roommate in this city. NWS San Francisco has been issuing alerts for "tule fog" snaking in from the Delta and North Bay valleys. It’s been thick enough to drop visibility to a quarter-mile in places like Concord. While the city center usually stays a bit clearer, morning commuters should expect some "socked-in" conditions through Tuesday morning before the sun burns it off around 10 or 11 AM.
Why the Rain Matters Right Now
Historically, January is one of our wettest months. We’ve already seen some heavy hitters earlier this month—like that 1.32-inch soak on January 4.
The fact that we’re seeing a dry stretch from the 18th to the 23rd is actually a bit of a reprieve. But keep an eye on the end of the month. Long-term outlooks suggest a much stormier pattern returning around January 27, where we might see 15-20mm of rain in a single day.
Actionable Advice for Your Week:
- Check the webcams: Before you head to the Pacific side (Ocean Beach), check a live cam. It can be sunny in the Mission and a total white-out at the Cliff House.
- Layers are non-negotiable: The 12-degree swing between the day's high and low happens fast once the sun dips behind the Santa Cruz mountains.
- Plan outdoor treks for Tuesday: It's the only day this week with a "Sunny" rating and low wind.
- Morning Fog: If you're driving the 101 or the Richmond-San Rafael bridge before 9 AM, give yourself an extra 15 minutes for low visibility.
Keep your umbrella on standby for Saturday, but otherwise, enjoy the "chilly but dry" vibes of mid-January in the city.