If you live in the Inland Valley, you already know the drill. You wake up in Pomona and it’s 48 degrees, but by the time you’re grabbing lunch near the Fox Theater, you’re peeling off layers because it’s suddenly 80. People from the coast think we’re just "another part of LA," but the weather forecast for Pomona is a completely different beast.
Right now, we are sitting in a strange, beautiful, and slightly annoying pocket of January. Today, Wednesday, January 14, 2026, the sky is aggressively blue. We are hitting a high of 79°F today. That is nearly 15 degrees above the historical average of 65°F.
It’s confusing.
One minute you're thinking about the snow on Mt. Baldy, and the next you’re wondering if it’s too early to turn on the AC. Honestly, this is the classic Pomona "false spring" that catches everyone off guard.
The Immediate Outlook: Heat, Then the Drop
Don't get too comfortable in those t-shirts. The weather forecast for Pomona shows this mini-heatwave peaking right about now.
Tomorrow, Thursday, is going to stay hot—expect about 84°F. That’s basically summer weather in the middle of winter. The National Weather Service (NWS) is tracking a ridge of high pressure that is keeping things dry and warm across the San Gabriel Valley.
But look at the nights.
Tonight will dip down to 48°F. That is a 31-degree swing in a single day. If you’re heading out to dinner at Western Steak House or hitting up a night class at Cal Poly Pomona, you absolutely need a jacket. It’s that dry, desert-adjacent cold that gets into your bones the second the sun drops behind the hills.
🔗 Read more: Finding the Right Word That Starts With AJ for Games and Everyday Writing
By the time we hit the weekend, the temperatures start to normalize. We’ll see highs drifting back into the high 70s on Saturday and Sunday.
What’s Happening Next Week?
The big shift happens around Wednesday, January 21.
We’ve had a dry start to the year, but the long-range models are hinting at a pattern change. We’re looking at a transition toward "ENSO-neutral" conditions. Basically, the weak La Niña that’s been hanging around is losing its grip.
For us, that means a return to reality:
- Tuesday, Jan 20: Mostly sunny, high of 74°F.
- Wednesday, Jan 21: Turning cloudy, high of 71°F.
- Thursday, Jan 22: Early morning thunderstorms are currently on the map.
Yes, rain.
There is a 32% chance of precipitation next Thursday. It’s not a deluge, but after this week’s heat, it’s going to feel like a shock.
Why Pomona Weather Is So Weird
Geographically, we’re in a bit of a funnel. The Santa Ana winds love to whistle through the canyons to our east, which is why we get those random spikes in temperature and why your car is probably covered in a fine layer of dust right now.
💡 You might also like: Is there actually a legal age to stay home alone? What parents need to know
Unlike Santa Monica, we don’t get that marine layer to keep us cool during the day. We get the full brunt of the sun. But because we aren’t quite "Low Desert" like Palm Springs, we still get those chilly Pacific air masses settling in overnight.
It's a microclimate tug-of-war.
A lot of people rely on general "Los Angeles" forecasts. Big mistake. If you check the weather for LAX, it might say 68°F. Meanwhile, in Pomona, we’re roasting at 82°F. You have to look at the specific data for the Ontario International Airport (KONT) station or the Pomona Fairplex sensors to get the real story.
The Rain Factor: What to Expect for the Rest of January
Historically, January is one of our wettest months. We usually see about 2.7 inches of rain across four or five "wet" days. So far, 2026 has been a bit stingy.
Last year, the burn scars from the wildfires in the San Gabriels were a huge concern. This year, because we’ve been drier, the risk of debris flow is lower, but the NWS is still keeping a close eye on the storms projected for the end of the month.
If that system on January 22-23 holds together, we could see a decent soaking.
Dealing with the "Grey"
When the rain does come, it’s usually preceded by a significant increase in humidity. Right now, we’re at a very dry 32% humidity. When that jumps to 50% or 60% next week, it’s going to feel "muggy" by Southern California standards.
📖 Related: The Long Haired Russian Cat Explained: Why the Siberian is Basically a Living Legend
Actionable Tips for This Week
Since the weather forecast for Pomona is basically a rollercoaster right now, here is how you handle it:
The Wardrobe Strategy
Stop wearing heavy sweaters to work. You'll be miserable by 2 PM. Go with a light base layer and a windbreaker. The "onion method" is the only way to survive a 30-degree daily temperature swing.
Watch the Pollen
Dry, warm winds mean the Ash and Alder trees are already starting to fire off. If your eyes are itchy today, it’s not a cold—it’s the weather. Keep your windows closed during the afternoon when the breeze picks up.
Hydration for Plants
Your garden thinks it’s May. If you have citrus trees or young landscaping, give them a good soak tonight. This 80-degree heat will bake the topsoil faster than you think, especially since we haven't had a good rain in a couple of weeks.
Check the Tires
Big temperature swings affect tire pressure. If your "low tire" light comes on tomorrow morning when it's 48 degrees, don't panic. It’s likely just the air contracting. Drive a few miles, let the tires warm up, and check them at a gas station once the sun is up.
The rest of the month looks like a slow slide back into actual winter. Enjoy the heat while it lasts, but keep your umbrella near the front door starting next Tuesday. We’re finally going to see some of that January moisture we’ve been missing.
Check your local NWS dashboard or the Fairplex weather station for real-time updates as that Thursday storm front approaches.