You’ve probably heard the jokes about California weather—it’s always 75 degrees and sunny, right? Honestly, if you live in Windsor or you’re planning a trip to this slice of Sonoma County, you know that’s basically a myth. The weather forecast Windsor CA is actually a complex beast, influenced by a tug-of-war between the Pacific Ocean’s chill and the inland heat.
Right now, as of mid-January 2026, we’re seeing exactly how weird things can get. While the rest of the country might be battling "Arctic revenge" snowstorms, Windsor is sitting at a comfortable 62°F under mostly cloudy skies. But don't let that fool you. The humidity is hanging out around 59%, and there’s a sneaky 10% chance of rain today, Saturday, January 17.
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It’s that weird time of year where you need a heavy coat at 7:00 AM and short sleeves by lunch.
The Russian River "Air Conditioner"
What most people get wrong about Windsor is thinking it’s just like Santa Rosa or Healdsburg. It’s not. Because of its spot on the Santa Rosa Plain, Windsor is a prime target for the "Coastal Warm" microclimate. This means we get the heat, but we also get the fog.
Local experts, like those with the UC Master Gardeners of Sonoma County, point out that the Russian River acts like a giant straw. It literally pulls cool marine air from the coast through the Petaluma Gap and the river valley itself. This creates a massive "diurnal shift"—a fancy way of saying the temperature swings like crazy.
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Think about this: Today’s high is 63°F, but the low tonight is a bone-chilling 32°F. That’s a 31-degree drop. If you aren't packing layers, you're gonna have a bad time.
What the Forecast Looks Like This Week
If you’re looking at the weather forecast Windsor CA for the next few days, it’s actually looking pretty decent for January. We’re moving out of the "mostly cloudy" funk and into some actual Vitamin D territory.
- Sunday, January 18: Expect a high of 67°F and mostly sunny skies. It’s perfect for hitting the Town Green, though the low of 39°F means the morning frost will still be a thing.
- Monday, January 19: Pretty much a carbon copy of Sunday. High of 67°F, low of 39°F. Light southwest winds at 3 mph. Basically, it's peak Sonoma winter—crisp, clear, and quiet.
- Mid-week Shift: By Tuesday and Wednesday, things cool down a notch. We’re looking at highs of 65°F and 62°F respectively. The clouds start creeping back in, and by the following Tuesday (Jan 27), the rain chance jumps up to 75% at night.
Honestly, the "January thaw" is real here. While the historical average for January is usually a high of 58°F, we’re currently beating those numbers by nearly ten degrees. It’s great for the mood, but it makes the garden a bit confused.
The Humidity and Wind Factor
People ignore wind in Windsor because it usually feels like a gentle breeze, but it matters for how the "feels like" temperature hits you. Currently, we have a very light 2 mph wind from the south.
When the wind shifts to the northwest, like it’s predicted to do next Saturday (Jan 24) at 8 mph, that 58°F high is going to feel a lot more like 50°F.
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And then there's the humidity. At 76% (today's daily average), the air holds onto the cold. It’s a "wet cold" that gets into your joints. It’s why locals are obsessed with their Patagonia vests and puffer jackets. You might look like a walking sleeping bag, but at least you’re warm when the sun ducks behind the clouds.
A Quick Reality Check on Rainfall
Windsor usually gets hammered in the winter. Historically, February is the wettest month, averaging about 6 inches of rain. January isn't far behind. While the current 10-day window is looking relatively dry, don't get complacent.
The sliding 31-day rainfall average for this time of year is usually around 5.9 inches. We’ve had some dry years lately, but when the atmospheric rivers open up, Windsor can go from "mostly sunny" to "flood watch" in about twelve hours.
Actionable Tips for Navigating Windsor Weather
If you want to handle the weather forecast Windsor CA like a pro, stop looking at the "High" temperature and start looking at the "Low."
- The 10:00 AM Rule: In Windsor, the fog usually burns off by 10:00 AM. If it’s still gray at 11:00 AM, cancel your picnic plans—it’s staying cloudy all day.
- Frost Protection: With lows hitting 32°F tonight, cover your succulents. Even though it was 60+ degrees today, that overnight dip will turn your plants to mush.
- Driving Hazards: Watch out for "Tule Fog." It’s that thick, pea-soup fog that settles on Highway 101 between Windsor and Santa Rosa. Visibility can drop to near zero in seconds.
- Hydration Matters: It’s dry here, even in winter. With humidity dropping to 59% during the day, you’ll dry out faster than you realize.
Basically, the weather here is a game of extremes. Enjoy the 67°F sun while it lasts this weekend, because the rain and the 38°F nights are always just around the corner. Pack a jacket, keep an eye on the northwest winds, and maybe keep an umbrella in the trunk just in case that 10% chance of rain decides to find your specific zip code.