If you’ve lived in Marin long enough, you know the drill. You leave your house in San Rafael and it’s a standard California morning, but by the time you hit the Coffee Roastery in downtown Fairfax, you’re suddenly enveloped in a thick, soup-like fog that feels ten degrees colder. Honestly, the fairfax ca weather hourly patterns are some of the most erratic in the Bay Area, and if you aren't checking the forecast by the hour, you're basically guessing.
Today, January 16, 2026, is a perfect example of why generalizations about Northern California weather fail here.
Right now, as of 9:11 AM, it's a crisp 49°F and sunny. But don't let that morning chill fool you. While the northeast wind is barely a whisper at 4 mph, the humidity is sitting high at 70%. It feels damp. It feels like winter. Yet, the high for today is pegged at 66°F. That is a massive swing for a small town tucked into the hills.
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The Morning Fog Trap
Most people waking up in Fairfax today dealt with a Dense Fog Advisory that didn't lift until 9:00 AM. If you were trying to commute or hit the trails at Cascade Falls early, you were likely squinting through a grey wall.
Here is the thing about Fairfax: it sits in a transitional climate zone (Sunset Zone 15, for the garden nerds). This means we get more frost than our neighbors in San Anselmo but way more heat than the folks out in Point Reyes.
- 10 AM: Things start to move. We’re looking at 53°F with the sun finally winning the battle against the leftover mist.
- 12 PM: This is the sweet spot. We hit 60°F.
- 2 PM - 4 PM: The "Fairfax Furnace" effect kicks in slightly. We peak at 62°F to 66°F.
- 6 PM: The sun dips behind the ridges, and the floor drops out. We’re back down to 53°F.
The jump from a low of 41°F tonight to a mid-60s afternoon means you’re essentially living through three different seasons in an eight-hour span. If you're wearing a heavy puffer at 2 PM, you're going to be miserable. If you're in a t-shirt at 6 PM, you're shivering.
Why the Hourly View Actually Matters
You've probably noticed that Fairfax stays "green" longer than the rest of the county. That’s because our annual rainfall averages nearly 47.5 inches, significantly higher than the California average. Even on a "sunny" day like today, the moisture levels are high.
The microclimates here are aggressive. One block is shaded by ancient redwoods and stays 55 degrees all day; two blocks over, a south-facing hillside is baking in 70-degree direct sun. This isn't just "weather"—it's a topographical mood swing. According to data from the UC Marin Master Gardeners, these shifts happen because Fairfax is effectively an "upland" inland area. We catch the marine layer as it tries to crest the ridges, but we also trap the heat in our narrow valleys.
What to Actually Do With This Info
Look, stop looking at the "Daily High" and thinking you're set.
First off, check the wind direction. Today it's coming from the northeast. That's a dry, land-based wind. It’s why the humidity is dropping from its morning high of 70% down to a predicted 58% by this afternoon. This makes the 66-degree high feel a bit "sharper" and the evening chill feel more biting.
Secondly, if you're planning on being outdoors, 11 AM to 3 PM is your window. The UV index is low (only a 2 today), so you won't fry, but that's when the "real feel" actually matches the thermometer.
Next Steps for the Fairfax Local:
- Layers are a religion: Start with a base layer that wicks moisture—remember, 70% humidity makes you sweat even when it's cool.
- Watch the Ridge Line: If you see clouds "pouring" over the hills toward Bolinas Road, the temperature is about to plummet 5 degrees in twenty minutes.
- Garden Check: Since tonight hits 41°F, it's not a freeze, but it's cold enough to stress young succulents that were just baked in the 66-degree afternoon sun. Give them a light watering now to help the roots handle the temp swing.
The fairfax ca weather hourly forecast is basically a guide on how to avoid being the person caught in a fleece jacket during a heat spike or a tank top during a fog roll-in. Stay updated, watch the northeast breeze, and enjoy the sun while it lasts—tonight will be clear, but it's going to be a cold one.