You’ve heard the quote. The one about the coldest winter being a summer in San Francisco. It’s basically the city’s unofficial slogan at this point, but honestly, it’s also a warning. If you’re checking the san francisco ca weather forecast today, January 18, 2026, you’re looking at a classic winter snapshot that looks mild on paper but feels entirely different once you’re standing on a corner in the Richmond District.
Right now, it’s 50°F out there. Not exactly freezing, right? But with 81% humidity and a 10 mph wind coming straight off the North Pacific, it "feels like" 45°F. That’s the thing about this city—the numbers never tell the whole story. You’ve got a mostly cloudy sky tonight, and while there’s only a 10% chance of rain, that dampness has a way of sinking into your bones.
Why the Sunday Forecast is Deceiving
Today, Sunday, January 18, we’re expecting a high of 59°F and a low of 49°F. It’s going to be partly sunny. Sounds like a nice stroll in Golden Gate Park, doesn't it? Well, kinda.
The UV index is sitting at a 2, so you aren't going to burn, but the north wind is staying steady at 10 mph. In San Francisco, a 10 mph wind isn't just a breeze; it’s a heat-thief. If you’re in the Sun Belt—think Noe Valley or the Mission—you might actually feel that 59 degrees. But if you’re near the SFO bridge approach or the Sunset, you’ll be reaching for a hoodie by noon.
The National Weather Service is currently tracking a "thermal belting" phenomenon in the region. Basically, we’ve got warm air trapped in the mountains while the cold air settles in the valleys and city streets. It’s why you might see 70°F on a ridge just a few miles away while you're shivering in 40-degree fog at the surface.
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The Week Ahead: Sunny Days and "Tule" Fog
Looking at the san francisco ca weather forecast for the rest of the week, we’re actually in a pretty dry stretch. Monday is looking sunny with a high of 60°F. Tuesday and Wednesday will dip back into the high 50s with more cloud cover.
Here is the breakdown of what to expect:
- Monday: Sunny, high 60°F, low 48°F. Wind drops to 5 mph. This is your best day for the Ferry Building.
- Tuesday: Mostly cloudy, high 58°F, low 47°F.
- Wednesday: Cloudy, high 58°F, low 49°F.
- Thursday/Friday: Bright sun returns, but highs stay steady at 58°F and 57°F.
We are currently in a transition period. Meteorologists at the Climate Prediction Center noted that the La Niña pattern that’s been hanging around is weakening. There’s a 75% chance we move into "ENSO-neutral" conditions by March. What does that mean for you? Less predictability. While the ridge of high pressure is keeping us dry for now, there’s a legitimate signal for wet weather returning the last week of January. Some models are hinting at up to 2.5 inches of rain at SFO between the 27th and the 31st.
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The Microclimate Reality Check
San Francisco isn't one city; it’s a collection of about 40 different weather zones. You can literally walk from a t-shirt climate to a parka climate in twenty minutes.
The "Fog Belt" (Richmond, Sunset, Ocean Beach) is currently living in that misty, cool reality. Meanwhile, the "Sun Belt" (Mission District, Potrero Hill) is soaking up whatever radiation manages to pierce through the high clouds. If you’re planning your day, don't just look at the city-wide average. If the forecast says 59°F, the Mission might be 64°F and Ocean Beach might be 54°F.
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How to Actually Dress for This
Stop packing for "California." Pack for a chilly autumn day in London that might occasionally turn into a spring morning in San Diego.
- The Base Layer: A breathable cotton or merino tee.
- The Mid-Layer: A light hoodie or a Patagonia-style puffer. This is the San Francisco uniform for a reason.
- The Shell: A windbreaker. The wind is the real enemy here, not the temperature.
- Footwear: Leave the flip-flops in the hotel. Between the hills and the damp pavement, you want sneakers or boots with grip.
Honestly, the best advice is to check a neighborhood-specific app like "Mr. Chilly" before you leave your Airbnb. The san francisco ca weather forecast you see on the news is usually recorded at the airport or downtown, and neither of those places might represent where you’re actually standing.
Actionable Steps for Your Visit
- Watch the Fog: If you want that iconic Golden Gate Bridge photo, go early or late, but be prepared for "Karl the Fog" to completely hide the spans.
- Plan for the "Wedge": The wind usually picks up around 3:00 PM. If you’re doing outdoor dining, try to book for lunch rather than a late dinner.
- Monitor the Shift: Keep an eye on the 500 mb flow patterns mentioned by the NWS. If that ridge erodes by next weekend, that 10% rain chance is going to spike.
The city is beautiful right now, even with the "pesky" high clouds. Just don't let the 60-degree forecast fool you into leaving your jacket behind. You’ll regret it the second you hit the shadows of the Financial District.