Honestly, if you're standing outside in Jefferson County right now, you already know the vibe. It’s cold. Like, "don't leave your coffee on the car roof for two minutes" cold. Today, Saturday, January 17, 2026, the actual temperature in Arnold Missouri is sitting at a crisp 23°F.
But here’s the thing—the thermometer is a bit of a liar today. Thanks to a 13 mph wind kicking in from the west, it actually feels like 11°F out there.
If you're planning to head over to the Meramec River or just running into the Schnucks on Richardson Rd, you're going to want the heavy coat. We’re looking at a high of 24°F today, which basically means we’ve already seen the best the sun has to offer. Tonight, it’s going to dip down to 12°F. It's that classic Missouri winter junk where the air just feels sharp.
The Reality of the Temperature in Arnold Missouri Right Now
Current conditions are showing partly sunny skies, but don't let the brightness fool you. The humidity is hanging around 55%, and there’s a tiny 5% chance of some stray flakes. It’s pretty typical for January in this part of the world.
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Historically, January is the coldest month we deal with in Arnold. Usually, we see highs around 42°F and lows near 26°F. Today is significantly colder than the "average," which just goes to show that Missouri weather doesn't really care about your spreadsheets or long-term averages.
What to expect for the rest of the week
If you hate this 20-degree business, I've got some sort of good news. Tomorrow, Sunday, January 18, we’re actually going to see a bit of a "warm-up" to 34°F. I mean, it’s still above freezing, so we’ll take what we can get.
Monday is going to be a bit of a buzzkill, dropping back down to a high of 21°F. But wait for Tuesday and Wednesday. We’re looking at 41°F and 46°F respectively. That’s almost picnic weather compared to today’s 11-degree wind chill.
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Why Arnold Feels Different Than St. Louis
You’ve probably noticed that the temperature in Arnold Missouri often feels a few degrees different than if you were standing in downtown St. Louis or even up in St. Charles. A lot of that comes down to the geography. We’ve got the hills and the river influence that creates these little micro-pockets of cold air.
- The River Effect: Being tucked near the confluence of the Meramec and Mississippi can trap moisture, making the cold feel "wetter" and more bone-chilling.
- Elevation: Some of the residential ridges in Arnold sit higher than the city basin, catching more of that 13 mph west wind we're seeing today.
- Urban Heat Island: Unlike downtown, Arnold has more open space and less concrete to hold onto the sun's heat during the day.
How to Handle This Cold Snap
Look, I'm not your mom, but 11°F (the "feels like" temp) is the zone where frostbite actually starts becoming a conversation if you're outside too long.
First off, check your tire pressure. These sudden drops from the 40s down to the 20s make that "low tire" light pop on like clockwork. It’s just physics—cold air is denser.
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Secondly, if you’ve got outdoor pets, bring them in. If it’s too cold for you to stand in the yard in a flannel, it’s too cold for them.
Lastly, watch out for the "Arnold black ice" spots. Specifically, those turns near the lower parts of Jeffco Blvd and the bridge overpasses. Even with only a 5% chance of snow, the moisture from the 60% humidity forecast can freeze on the pavement when the sun goes down and the temp hits that 12°F low tonight.
Actionable Steps for Arnold Residents Today
Basically, stay warm and be smart.
- Layer up before 4:00 PM: The sun is going to lose its strength early, and that 12°F low is going to creep in faster than you think.
- Drip the faucets: If you live in an older house near the historic parts of town with crawl spaces, tonight’s low is deep into the pipe-bursting territory.
- Plan your errands for Wednesday: If you have outdoor chores, Wednesday’s 46°F is going to feel like a tropical vacation compared to this weekend.
Keep an eye on the west wind. It’s the main reason today feels like 11°F instead of 23°F. Stay safe out there on the roads, and maybe just stay inside with some chili.