You’ve probably heard the jokes. If you don't like the weather in Idaho, just wait five minutes. While that’s a bit of an exaggeration, anyone looking at the idaho falls idaho 10 day weather forecast right now knows that "predictable" isn't exactly the word we'd use.
Honestly, mid-January in the Snake River Plain is a weird time. We’re currently sitting in a stretch where the sun is out, but the air still bites. Today, January 15, 2026, we’re looking at a high of 37°F. That sounds almost balmy if you’ve lived through the -20°F stretches we occasionally get, but don't let the sunshine fool you. The humidity is hovering around 74%, and with a light southwest wind, it feels a lot more like a refrigerator than a winter wonderland.
What the idaho falls idaho 10 day weather forecast really looks like
If you’re planning your week, you’ve got to look at the trend, not just the daily high. We are heading into a remarkably dry and stable period for the next few days, followed by a shift that’ll probably make your morning commute a bit more interesting.
The immediate Outlook: January 16 – January 19
Tomorrow, Friday the 16th, keeps the trend going. We're expecting a high of 37°F and a low of 19°F. It’ll be partly sunny, which basically means you’ll want your sunglasses for the glare off the existing snowbanks, but you’ll still need the heavy parka.
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Saturday and Sunday (the 17th and 18th) are going to be crisp. We’re talking highs of 35°F and 38°F respectively. The big thing to watch is the overnight lows. We’re dropping down to 16°F on Sunday night. If you haven't unhooked your hoses or checked your pipe insulation, this is your final warning before the deep freeze sets in.
The Mid-Week Shift: January 20 – January 22
Monday the 19th starts off sunny, but by Tuesday the 20th, the clouds start rolling in. The idaho falls idaho 10 day weather forecast shows a transition to "mostly cloudy" as we hit the middle of next week.
Temperatures stay fairly consistent—lows in the high teens and highs in the mid-30s—but the moisture begins to creep back into the valley. By Thursday the 22nd, we’re looking at a high of 42°F. Now, in most places, 42°F sounds nice. In Idaho Falls in January? It usually means we're trading "dry cold" for "slushy mess."
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Why Idaho Falls weather is so hard to pin down
Most people don't realize that Idaho Falls sits at an elevation of about 4,700 feet. We are essentially in a high-desert bowl. This creates a phenomenon called an "inversion."
Basically, cold air gets trapped on the valley floor while warmer air sits on top of it. This is why you can sometimes drive up to Kelly Canyon or toward Jackson and find it 10 degrees warmer than it is in downtown Idaho Falls. When the inversion is set, the idaho falls idaho 10 day weather forecast might say "sunny," but you’ll be stuck in a gray haze of freezing fog that refuses to budge.
The late-week "Surprise"
Toward the end of this 10-day window, specifically Friday, January 23, things get messy. We have a 20% to 35% chance of a rain and snow mix.
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With a high of 38°F and a low of 26°F, it's that classic "will it stick or will it freeze?" scenario. For those of us driving I-15 or Highway 20, this is the most dangerous kind of weather. It’s not the deep snow that gets you; it’s the thin layer of ice that forms when rain hits a frozen road surface at night.
Real talk: What you actually need to do
Forget the generic "wear layers" advice. If you’re living through the next 10 days in the 83401 or 83402 zip codes, here is the reality:
- Check your tires now. We are about to go from dry roads to a cycle of melting and refreezing. If your treads are thin, that Friday the 23rd commute is going to be a nightmare.
- Top off the washer fluid. The "high" of 42°F next Thursday means the roads will be covered in that salty, gray Idaho sludge. You’ll go through a gallon of washer fluid in two days just trying to see through your windshield.
- Morning Warm-ups. With lows hitting 16°F this Sunday, give your vehicle at least 5-10 minutes. It's not just about the engine; it's about making sure your defroster actually works before you're halfway down Sunnyside Road.
The idaho falls idaho 10 day weather forecast suggests a relatively "mild" January by our standards, but in Eastern Idaho, "mild" is a relative term. We aren't seeing any -30°F record-breakers this week, but the constant fluctuation between 16°F and 42°F creates its own set of problems.
Stay ahead of the freeze-thaw cycle. Keep an eye on the wind speeds toward the end of next week, as those southwest gusts of 15 mph will make that 38°F feel significantly colder. Most importantly, don't trust the sun—it’s a liar this time of year.
Next Steps for Your Week:
- Clear any ice buildup from your gutters during the Wednesday/Thursday "warm" spike to prevent ice dams.
- Plan your grocery runs for Saturday or Monday to avoid the potential slush and wind-blown snow forecasted for the following Friday.