So, you’re flying into San Francisco International. Or maybe you're headed out. Either way, you've probably checked the weather app and seen that generic "cloudy" or "chance of rain" icon and figured you’re good to go. Honestly? That’s usually the first mistake people make when looking at an sfo weather forecast 14 days out. SFO doesn't play by the same rules as the rest of the country. It doesn't even play by the same rules as downtown San Francisco, which is just 13 miles up the road.
The airport is a microclimate beast.
Right now, as we sit in mid-January 2026, the current conditions at San Francisco are hovering around 51°F. It's nighttime, the air is 70% humid, and there's a light breeze coming out of the northeast at about 4 mph. If you’re looking at the immediate horizon, today (Saturday, January 17) is staying pretty steady with a high of 59°F and a low of 49°F. It's cloudy. It'll stay cloudy. But for a traveler, the real story isn't the temperature—it's the wind and the visibility.
The 14-Day Outlook and the "Southeast Plan" Trap
When you scan an sfo weather forecast 14 days in advance, you’re looking for the "Southeast Plan." Most of the time, the wind at SFO blows from the west. This is the "West Plan," and it’s how the airport was designed to work. It allows for dual simultaneous landings. It’s efficient. It’s fast.
But about 5% of the time—usually during these winter months—the wind flips.
If those forecasts start showing winds from the south or southeast, even at a "gentle" 10 mph, the airport has to switch its entire flow. We saw this earlier this month, on January 2, when an atypical wind pattern delayed over 160 flights. When SFO has to use the Southeast Plan, the arrival rate drops from 60 planes an hour to about 30. Basically, you’re looking at a 50% capacity cut just because the wind decided to change direction.
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Looking at the next two weeks, the winds are staying mostly north/northeast. Tomorrow, Sunday the 18th, expects a high of 60°F and a low of 49°F with northeast winds at 5 mph. Monday the 19th looks even clearer, hitting 61°F with 0% chance of rain. For now, the "West Plan" is safe. But keep an eye on Tuesday the 20th and Wednesday the 21st. Humidity is spiking to 77% and 74%, and we’re seeing "mostly cloudy" conditions return. That’s when the ground delay programs usually start creeping in.
Why the 14-Day Window is Kinda Sketchy
Let's be real: any 14-day forecast is a guess. But at SFO, it’s a guess wrapped in a riddle. The airport sits right on the edge of the Bay, and the "tule fog" that rolls in during the winter is different from the famous summer "Karl the Fog" marine layer. Tule fog is thicker. It’s heavier. It forms over the Central Valley and "sloshes" into the Bay.
If your sfo weather forecast 14 days out shows high humidity (above 80%) and low winds (under 5 mph) during a cold snap, you’re looking at a recipe for a "Category III" morning. That’s pilot-speak for "we can’t see the runway until we’re practically on it."
Check out the trend for later next week:
- Thursday, Jan 22: High 57°F, Low 47°F, 82% humidity.
- Friday, Jan 23: High 56°F, Low 47°F, 86% humidity.
- Saturday, Jan 24: High 56°F, Low 47°F, 81% humidity, and a 20% bump in rain chance.
Those humidity numbers are the red flag. When it hits 86%, you aren't just looking at clouds; you're looking at a potential soup.
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Rain vs. Flight Delays: The Real Math
People worry about rain. Don't. SFO handles rain just fine. It’s the clouds that come with the rain that cause the headache.
On January 26, the 10-day mark, the forecast is calling for "light rain" at night with a 20% chance of precipitation and northeast winds at 6 mph. Temperatures will be a crisp 58°F/47°F. Now, 20% rain sounds like nothing, right? Wrong. In the Bay Area, that often means a "marine surge" or a low-pressure system that drops the cloud ceiling to 1,000 feet.
When the ceiling drops, SFO loses its ability to land two planes at once. They have to stagger them. This is why you see a "normal" status on FlightAware or the FAA's website, yet your flight is still 45 minutes late. It’s a "gate hold." The FAA is literally keeping planes on the ground in Los Angeles or Seattle because there isn't enough space in the air over San Mateo to stack them all.
Specifics to Watch for Your Trip
If you're looking at the sfo weather forecast 14 days out for a specific flight, here is the expert breakdown of what actually matters:
- The Dew Point/Temperature Spread: If the temperature and the dew point are within 2 or 3 degrees of each other, fog is almost a certainty. On Jan 16, the dew point was 52°F while the air was 53.9°F. That’s a tiny gap.
- Wind Direction (Not Speed): Northeast is fine. West is great. South or Southeast? Prepare for a long day at the Bourbon Pub in Terminal 3.
- UV Index: It’s currently 0 to 2 for the next two weeks. This sounds irrelevant, but a low UV index means the sun isn't strong enough to "burn off" the morning fog quickly. If it doesn't burn off by 10:00 AM, the delays cascade through the entire afternoon.
Actionable Tips for SFO Travelers
Don't just stare at the 14-day forecast and hope for the best. Be proactive. If you see humidity climbing above 80% for your travel date, or a "mostly cloudy" prediction with south winds, book the first flight of the morning. 6:00 AM flights are rarely delayed by weather because the backlog hasn't started yet.
Also, watch the "marine layer" depth. A deep marine layer actually creates higher ceilings (better for landing). A shallow one (less than 1,000 feet) is the one that shuts down runways.
Honestly, the best thing you can do is check the FAA’s National Airspace System (NAS) status alongside your weather app. If the app says "sunny" but the FAA says "Ground Delay Program," it means the weather at the airport is doing something the rest of the city isn't.
Monitor the transition on Monday, January 26. That light rain and increased cloud cover mark a shift from the clear "high pressure" days we're seeing this weekend. If that moisture sticks around into late January, the end of your 14-day window could get messy. Stay ahead of it by checking the wind direction 48 hours before you head to the curb. Northeast is your friend; Southeast is your sign to pack an extra snack for the gate.