Honestly, if you’re planning a trip through the Inland Empire, you’ve probably heard the jokes about the wind. Or the heat. But the reality of weather for fontana ca is a bit more nuanced than just "it's hot and windy."
Today, January 18, 2026, it’s actually looking pretty decent out there. The current temperature is sitting at 76°F, which is basically a gift for mid-January. It’s mostly cloudy right now with a northwest wind barely moving at 1 mph. You’d hardly notice it. But don't let the calm fool you; this city has a personality that shifts faster than a Fontana Speedway pit crew.
The Cajon Pass "Wind Tunnel" Effect
Most people think the Santa Ana winds are just a Southern California thing. They are. But Fontana gets the "VIP" treatment because of the Cajon Pass.
Basically, the pass acts like a giant nozzle. When high pressure builds over the Great Basin (the desert area to our east) and low pressure sits off the coast, the air has to go somewhere. It gets squeezed through that gap in the mountains. By the time it hits North Fontana, it’s compressed, heated up, and moving fast.
I’ve seen car doors nearly ripped out of hands during a nasty gust. It’s not just "breezy." It’s a physical force.
What to Expect This Week
If you're looking at the immediate forecast, keep your sunglasses handy for a bit longer.
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- Monday (Jan 19): High of 80°F and sunny.
- Tuesday (Jan 20): 78°F and mostly sunny.
- Wednesday (Jan 21): Things start to shift. It'll be cloudy with a high of 73°F.
- Thursday (Jan 22): Here comes the change. There's a 40% chance of light rain with a high of only 68°F.
It’s a classic Inland Empire winter rollercoaster. You go from wearing a t-shirt on Monday to hunting for a windbreaker by Thursday.
The "June Gloom" Misconception
A lot of people think Southern California is 365 days of pure sunshine. Not true.
In late spring and early summer, we get what locals call "June Gloom." In Fontana, this usually looks like a thick marine layer that rolls in overnight. It makes the mornings feel misty and cool, almost like you’re in a different state. Usually, it "burns off" by 1:00 PM or 2:00 PM, but some days it just hangs out.
If you hate the heat, June is actually a sneaky-good time to be here. August is the real beast. That’s when you’ll see highs consistently in the mid-to-high 90s, sometimes cracking 103°F.
Fire Season and Dry Air
We have to talk about the humidity—or the lack of it. Right now, the humidity is a bone-dry 11%.
When the Santa Anas kick up and the humidity drops into the single digits, the fire risk in the foothills becomes extreme. This isn't just "weather talk." It’s a reality of living here. About 53% of buildings in Fontana are considered at high risk for wildfire because of this specific combination of wind and dryness.
Survival Tips for the Fontana Climate
If you're moving here or just passing through, don't just check the temperature. Check the wind speed.
- Hydrate more than you think. 11% humidity pulls moisture right out of you. You won't even realize you're sweating because it evaporates instantly.
- Secure your trash cans. Seriously. If the forecast mentions "North winds" over 20 mph, your bins will end up three houses down.
- The "Layer" Rule. Even on an 80°F day in January, the temperature will plummet to 50°F the second the sun goes down. Never leave the house without a hoodie in the trunk.
The weather for fontana ca is manageable once you understand the geography. It’s a place where you can suntan in the morning and need a heater by dinner. Just keep an eye on those mountain passes; they tell the real story of what’s coming.
Actionable Next Steps:
Check your tire pressure if a cold front is moving in on Thursday; the sudden drop from 80°F to 68°F often triggers those annoying dashboard sensors. If you're in North Fontana, clear any loose patio furniture before the northwest winds pick up later this week.