Highland, California, is a weird place when it comes to the sky. It’s tucked right against the base of the San Bernardino Mountains, and honestly, that geography dictates every single thing you feel when you walk outside. Most people think Southern California is just "sunny and 75" year-round.
That is a total myth.
If you’re moving here or just visiting, you’ve got to realize that the weather in Highland CA is a game of extremes. One week you’re hiding from a 105-degree heatwave, and the next, you’re watching the Santa Ana winds try to rip the shingles off your roof. It’s localized. It’s intense. And if you don't know the patterns, you're going to be miserable.
The Summer Sizzle is No Joke
July and August are basically a test of endurance. While coastal cities like Santa Monica are enjoying a nice breeze, Highland is baking. Because we’re inland, the marine layer—that cool fog that saves the coast—usually burns off before it ever hits the 210 freeway.
The numbers don't lie. Average highs in July hit around 95°F, but let's be real: we see plenty of days cracking 100°F or even 105°F.
It’s dry heat. That "at least it's not humid" thing people say? It’s true, but it also means the moisture is sucked out of everything. Your skin, your plants, the hills—everything turns brittle. This is when the "Urban Heat Island" effect kicks in hard. The asphalt in the shopping centers near Greenspot Road holds that heat way into the night. Even after the sun drops behind the mountains, you might still be looking at 70°F or 75°F at midnight.
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Why the "Windy" Reputation is Earned
Then comes the wind. If you live here, you know the sound. It starts as a low whistle and turns into a roar.
The Santa Ana winds are a legendary part of the weather in Highland CA. These aren't your typical breezes; they are high-pressure systems from the Great Basin that get squeezed through the Cajon Pass. As the air drops in elevation, it heats up and speeds up. We’ve seen gusts hit 60 to 70 mph easily.
It’s spooky. The sky gets eerily clear—like, you can see every crag on the mountains—but the air feels like a giant hair dryer is pointed at your face. Humidity can drop to 5% or lower. This is peak wildfire season territory. When those winds kick up in October or November, everyone in Highland is on high alert. The proximity to the San Bernardino National Forest means a spark anywhere nearby is a major problem for the neighborhoods bordering the foothills.
Winter: The Season of "Wait, It’s Actually Cold?"
People forget that Highland actually gets a winter. It’s short, sure, but it’s there.
By December and January, those triple-digit days are a distant memory. Daytime highs usually hover around 65°F, which is perfect hiking weather. But the nights? They get crisp. It’s not uncommon to wake up to frost on your windshield if you’re parked outside. Lows regularly dip into the low 40s or even high 30s.
Rain is the other big factor. Highland gets about 15 to 18 inches of rain a year on average, mostly between January and March.
- Atmospheric Rivers: These are the big players. They dump inches of water in a few hours.
- Flash Flooding: Because we’re at the base of the mountains, all that water has to go somewhere.
- Snow: You won’t see snow on the ground in the city very often, but you’ll see it on the peaks right above you. It’s a cool vibe—wearing a t-shirt in your backyard while looking at a snow-capped Mt. San Gorgonio.
The Microclimate Reality
Highland is split. You’ve got the lower elevations near San Bernardino, and then you’ve got "Upper Highland" as you climb toward East Highland Ranch.
The temperature difference between the two can be 3 to 5 degrees on any given day. The higher you go, the windier it gets. If you’re living up near the hills, you’re going to deal with more "orographic lift"—which is just a fancy way of saying the mountains force the clouds up, making it rain more in the foothills than it does just a few miles south.
Actionable Tips for Living with Highland Weather
If you want to survive the local climate without losing your mind (or your lawn), here is the practical reality of what you need to do:
- Landscape for Fire, Not Just Looks: If you live near the foothills, "defensible space" isn't an option; it's a necessity. Clear the dry brush. Use fire-resistant plants like succulents or deep-rooted oaks instead of oily pines.
- The 10 AM Rule: During the summer, do not—I repeat, do not—try to do yard work or go for a run after 10:00 AM. The heat peaks fast. If you aren't done by mid-morning, wait until the sun is actually behind the mountain ridge in the evening.
- Check Your Shingles: Before the Santa Ana season hits in the fall, check your roof. Those winds will find any loose shingle and turn it into a kite.
- Invest in Good Filters: Between the dust kicked up by the winds and the occasional wildfire smoke trapped in the Inland Empire basin, the air quality can get rough. A high-quality HVAC filter (MERV 13 or better) makes a massive difference for your lungs.
- Water at Night: If you water your grass at noon in Highland, half of it evaporates before it hits the roots. Set your timers for 2:00 AM or 3:00 AM to actually keep things green.
The weather in Highland CA is essentially a cycle of "beautiful," "too hot," and "hold onto your hat." It’s rugged, but that’s the price you pay for living right at the gates of the mountains. Just keep an eye on the Cajon Pass reports and keep your AC tuned up; you’ll be fine.