Honestly, if you're standing outside in Balboa Park right now, you aren't thinking about "averages" or "climate trends." You're probably just wondering why you didn't bring a slightly thicker hoodie. Or maybe you're realizing that 64°F in the shade feels a lot different than 64°F in the sun.
That’s the thing about the temperature now in San Diego. It’s tricky.
Right this second, the thermometer is sitting at 64°F. That was recorded at 5:05 PM PST. It’s sunny, which helps, but the humidity is hovering at 52%. It’s that crisp, dry air that defines a Southern California winter. We aren't sweating, but we aren't exactly freezing either.
The Reality of San Diego’s "Goldilocks" Weather
People think San Diego is just 72 degrees and sunny every single day of the year. Not true. Especially not today, Sunday, January 18, 2026.
We actually hit a high of 75°F earlier this afternoon. That's pretty warm for January! But don't let that fool you into thinking the night will be just as mild. The low for tonight is expected to drop all the way down to 53°F. That is a 22-degree swing.
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If you’re planning on being out past sunset, you’re going to feel that.
The wind is barely a factor right now, coming from the northwest at a lazy 3 mph. It’s basically a light breath of air off the Pacific. But according to the National Weather Service, the marine layer is going to start building back in tonight.
What does that mean for you? Fog.
Specifically, if you’re within five miles of the coast—think La Jolla, Ocean Beach, or even down toward Imperial Beach—you might see some pretty dense fog rolling in late tonight and into Monday morning. The visibility could drop significantly.
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Why the "Microclimate" Matters More Than the App
San Diego is a city of microclimates. You can’t just look at one number and call it a day.
- Coastal areas: Usually cooler during the day and warmer at night because of the ocean's "insulation."
- Inland valleys: Places like El Cajon or Santee often bake in the 80s while the coast stays in the 60s.
- The Mountains: Palomar Mountain already saw over 5 inches of rain earlier this month. It's a different world up there.
Basically, if you’re moving more than ten miles in any direction, the temperature now in San Diego could change by ten degrees.
What’s Coming for the Rest of the Week?
The high pressure that’s been keeping us warm is going to hang around through Tuesday. In fact, some inland areas might even see highs near 78°F by then. But don't get too comfortable.
A cooling trend is slated to kick off on Wednesday. A low-pressure system is creeping toward us from the coast. While the chance of rain is currently low—less than 15% according to the latest model ensembles—the clouds are definitely coming back.
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It’s been a wild start to the year. Remember New Year’s Day? San Diego recorded 2.07 inches of rain in a single day. That officially made it the wettest New Year's Day on record for the city.
The good news? That rain officially wiped out the "Abnormally Dry" classification for the county. We are officially out of the drought for now.
Quick Facts for Your Sunday Evening:
- Current Temp: 64°F
- Humidity: 52% (Dry, but the fog is coming)
- Wind: NW at 3 mph
- UV Index: 0 (Sun is going down, no sunscreen needed now)
- Tonight's Low: 53°F under partly cloudy skies
How to Handle the San Diego "Chilly" Season
If you're a local, you know the drill. If you're visiting, listen up.
The most important thing you can do is dress in layers. A t-shirt for the 75°F peak and a solid jacket for the 53°F drop. It sounds like common sense, but the "dry cold" here hits differently when the sun disappears behind a building.
Also, keep an eye on the marine layer if you’re driving. That fog isn't just a mood; it’s a hazard. Visibility can drop to a quarter-mile in some pockets of the city tonight.
Next Steps for San Diegans:
- Prep for Fog: If you have an early commute Monday morning (MLK Day), give yourself an extra ten minutes. The coastal fog is expected to be thickest between 8:00 AM and 10:00 AM.
- Watering Plants: Since the humidity is relatively low (forecasted to hit 37% tomorrow), keep an eye on your garden. Even though we had a rainy start to the month, the dry offshore flow can suck the moisture out of soil fast.
- Sunset Watch: Sunset is right around 5:08 PM. If you're heading to Sunset Cliffs, the temperature will drop about 5 degrees the moment the sun hits the horizon. Bring the blanket.