Honestly, if you're living in or passing through the Inland Empire right now, you’ve probably noticed the air feels a bit different. It’s that weird Southern California winter where you’re wearing a hoodie at 7:00 AM and wondering if you should’ve worn shorts by lunchtime.
Basically, we’re looking at a stretch of weather in Fontana that is surprisingly warm for mid-January, but don't let the sunshine fool you into thinking it's smooth sailing.
The Immediate Outlook: Sunny and Significantly Warm
Starting today, Thursday, January 15, 2026, Fontana is sitting pretty with a high of 77°F. That’s a good 10 to 15 degrees above what we usually expect this time of year. Historically, Fontana averages a high of about 62°F to 64°F in January. We are way past that.
Tonight, it stays clear with a low of 57°F.
Tomorrow, Friday, January 16, the heat holds steady at 77°F. But here’s the kicker: the wind is starting to pick up. We’re expecting speeds around 14 mph coming from the north. If you’re sensitive to the Santa Ana patterns, you’ll likely feel that dry, crisp air moving in.
Breaking Down the Next 10 Days
You’ve gotta look at the trend here. We aren't staying in the high 70s forever.
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- Saturday, Jan 17: A slight dip to 75°F. Mostly sunny, but the humidity is dropping to a bone-dry 18%.
- Sunday, Jan 18: Still 75°F, but the clouds start rolling in. It’ll feel a bit gloomier, though it's still warm.
- Monday, Jan 19: Expect 74°F and mostly sunny skies. A perfect day for any outdoor MLK Day plans.
- Tuesday, Jan 20: The cooling trend begins. High of 73°F with some periodic clouds.
- Wednesday, Jan 21: We finally drop out of the 70s. High of 69°F. It’s going to feel "chilly" to locals, even though it's actually closer to our normal averages.
- Thursday, Jan 22: High of 67°F. There’s a tiny bit of moisture in the air (about 39% humidity), but only a 10% chance of actual rain.
- Friday, Jan 23: High of 66°F. Back to full sun.
- Saturday, Jan 24: High of 68°F and clear skies.
Why Does Fontana Weather Feel So Intense?
It’s the wind. It’s always the wind. Fontana sits right in the path of air channeling through the Cajon Pass. When those north/northeast winds hit (like we’re seeing this Friday and Saturday), they compress and heat up. That’s why we’re seeing 77-degree days while the rest of the country is freezing.
The humidity is also a factor. When it hits 18% like it will this Saturday, your skin and eyes will feel it. It’s "static shock" season.
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Real-World Advice for the Week
Don't pack away the sweaters, but definitely keep the sunscreen handy. The UV index is hitting a 3 on Friday—not extreme, but enough to catch you off guard if you're outside for a long hike at North Fontana’s parks.
Since the low temperatures are hovering between 47°F and 58°F, the "layering" rule is non-negotiable. You’ll want a light jacket for the morning commute, but you’ll be blasting the AC in your car by 2:00 PM.
Actionable Steps:
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- Hydrate your skin: With humidity dropping below 20% this weekend, grab the heavy-duty lotion now.
- Check your tires: Significant temperature swings (like 77°F down to 47°F) can mess with your tire pressure sensors.
- Fire safety: Those north winds and low humidity are the classic recipe for brush fire warnings in the foothills. Keep an eye on local alerts if you live near the northern edges of the city.
- Gardeners take note: The last frost usually doesn't hit until early March, so while it feels like spring, don't get too aggressive with sensitive planting just yet.
This 10 day weather forecast Fontana CA shows a transition from unseasonable warmth back to the standard, crisp January air we’re used to. Enjoy the 77-degree days while they last; by next Thursday, the "real" winter returns.