Honestly, if you’ve spent more than a week in the Central Valley, you know the modesto california weather forecast is basically a roll of the dice between "stunningly clear" and "I can't see the hood of my car."
Right now, as of Saturday, January 17, 2026, we’re staring at a classic winter setup. The current temp is sitting at a crisp 48°F. It’s cloudy. The air is heavy—humidity is pinned at 90%—and there’s barely a breath of wind coming from the southwest at 1 mph.
It’s that thick, soup-like atmosphere that makes Modesto feel like it’s wrapped in a wet wool blanket.
The Tule Fog Reality Check
Most people outside the valley think "winter" means snow or just "colder rain." Nope. In Modesto, winter is defined by the Tule Fog.
Earlier today, the National Weather Service (NWS) had a dense fog advisory out until noon. We're talking visibilities dropping to near zero on Highway 99 and I-5. It’s a phenomenon that happens because the high-pressure systems trap cool, moist air on the valley floor.
If you're driving to work and see the fog, don't use your high beams. Seriously. It just reflects back and blinds you. Stick to the low beams or fog lights if you've got 'em.
Today's Numbers (Saturday, Jan 17)
- High Temperature: 57°F
- Low Temperature: 41°F
- Wind: East at 3 mph
- Precipitation Chance: 10% (Day and Night)
- UV Index: 1 (Basically non-existent)
You've basically got a 10% chance of a light sprinkle, but mostly it's just going to stay gray and damp.
Looking Ahead: The Next 14 Days
The modesto california weather forecast for the rest of January looks surprisingly stable, if a bit chilly. Tomorrow, Sunday the 18th, is going to be a mirror of today—lots of morning fog with a high around 56°F and a low of 41°F.
By Monday and Tuesday (Jan 19-20), things might actually clear up a bit. We’re looking at highs creeping up toward 65°F with some actual sun peeking through. If you’ve been waiting to wash the car or do some yard work, that’s your window.
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But don't get too comfortable. The long-range outlook from groups like the Farmers' Almanac and local historical data suggests that late January usually brings our coldest snaps.
Why Modesto is "Warmer" than Fresno
There's this weird trivia bit locals love to argue about: why is Modesto often a few degrees warmer than Fresno during cold snaps?
Elevation plays a part, but it's mostly about the "thermal belt." Fresno is about 300 feet higher, and while it's closer to the equator, the cold air often drains into those slightly higher pockets differently. Modesto also sits a bit closer to the Delta, which can sometimes provide a tiny bit of moderating maritime influence, though not enough to save us from the frost.
The 2026 Climate Context
We’re currently in a weak La Niña pattern. Traditionally, people think La Niña means a dry winter for California, but that's not always the case for the Central Valley.
Data from the NWS Hanford office shows that since the 90s, La Niña years have actually trended slightly wetter for us. We're currently seeing about 3 inches of rain on average for January. This year, we’re mostly on track for that, though the "stormy" periods are expected to hit harder in late February.
What to Wear and How to Prep
If you’re heading out tonight or tomorrow, it’s sweater weather. Period.
With the humidity at 90%, 48°F feels a lot colder than it looks on paper. That dampness gets into your bones. A light, water-resistant shell is usually better than a heavy wool coat because of the mist and high humidity.
- For Commuters: Check the Caltrans QuickMap before you hit the 99. If the fog is thick, leave 20 minutes early.
- For Gardeners: The Tule Fog is actually great for the almond orchards—it provides the "chill hours" the trees need to go dormant and produce a good crop later. But keep an eye on your potted succulents; the high humidity can lead to root rot if they stay soaked.
- For Homeowners: Check your heater filters now. Since we spend so much time indoors during these "gloomy" weeks, air quality can get funky.
The modesto california weather forecast is rarely "exciting" in January, but it is persistent. Expect the gray to stick around for a few more days before we get that brief mid-week sunshine.
Next Steps for Modesto Residents:
Keep an ice scraper in your car even if it looks clear tonight; that 90% humidity loves to turn into a thin sheet of frost on windshields when the temp hits 41°F. If you're planning travel through the Grapevine or up toward Sacramento, monitor the NWS Hanford social media feeds—they are much faster with "instant" fog alerts than most weather apps. Lastly, take advantage of the sunny break predicted for Tuesday, January 20, to clear any debris from your gutters before the next potential rain cycle at the end of the month.