When you think about Christmas in Idaho, you probably picture snow-dusted mountains, chilly mornings, and that sharp winter air. That’s mostly accurate, but honestly, it depends a lot on where you end up in the state.
Usually, Christmas in Idaho means cold weather near freezing, with a decent chance of snow up in the mountains and a mix of rain or maybe some light snow in the lower valleys.
In Boise and the Snake River Plain, daytime highs often hang out in the 30s, and nights drop into the 20s. Snow might fall, but you can’t count on it every year.
If you head north or climb into higher elevations, your odds of waking up to a white Christmas go way up. Several inches of snow on the ground is pretty normal up there.
So, if you’re planning a holiday trip or just want to know what to expect for travel, it helps to get a feel for these patterns. Idaho’s different regions each bring their own twist to the holiday weather.
Typical Christmas Weather in Idaho
Christmas in Idaho usually brings cold temps, a mix of rain or snow depending on where you are, and those short winter days. Conditions swing a lot between southern cities like Boise and northern towns such as Sandpoint.
Average Temperatures in Late December
You’ll get cold days and freezing nights pretty much everywhere during Christmas week. In Boise, average highs usually hit 36–38°F, with lows near 25°F. Nights feel even colder with clear skies and a bit of wind.
Idaho Falls runs a bit colder. Highs land around 30°F, and lows dip into the mid-teens. Up in Sandpoint, you’ll see highs in the mid-30s and lows in the mid-20s.
So, you’ll want winter gear no matter your plans. If you’re getting outside, layer up and watch for icy mornings.
Afternoons warm up a bit, but they’re short. Boise gets about 9 hours of daylight in December, and it’s even less up north.
Precipitation Patterns Near Christmas
December brings both rain and snow, but what you get really depends on elevation and temperature. In Boise, December averages about 1.5 inches of rainfall spread over 8–10 days. Most of that comes as light rain, though snow does show up sometimes.
Idaho Falls and Sandpoint usually get more snow and less rain. Idaho Falls averages about 0.6 inches of liquid precipitation, while Sandpoint gets closer to 2.5 inches, mostly as snow.
Skies stay unsettled during Christmas week. Boise sees clear skies less than 45% of the time in December. Northern Idaho is even cloudier, with Sandpoint only getting about 24% clear days.
Snowfall Likelihood and Accumulation
Snow chances really jump around depending on where you are. In Boise, December snowfall averages 2–3 inches, and it tends to melt off pretty fast. A white Christmas in the city only happens about 25–40% of the time.
Idaho Falls averages 4–5 inches of snow in December, and seeing snow on the ground at Christmas is pretty common. Sandpoint up north gets even more, with 8–9 inches for the month.
If you’re chasing that classic snowy holiday, head north or climb into the mountains. Ski towns and higher elevations almost always have snow, while places like Boise might just have patches or even bare ground on Christmas Day.
Regional Variations Across Idaho
Idaho’s Christmas weather really shifts depending on where you are. Elevation and latitude both play a part, so don’t expect things to feel the same everywhere.
Weather Differences Between North and South
Northern Idaho—think Sandpoint or Coeur d’Alene—usually deals with colder, snowier weather in late December. Highs hover in the mid-30s °F, lows often hit the 20s °F, and snow falls often. Cloudy skies give everything that classic wintry vibe.
Southern Idaho, especially near Boise, stays milder. Daytime highs average around 38°F, and lows settle near 25°F. Snow is less common here, and precipitation might just be rain or a dusting of snow. Boise also gets more sunny breaks than the north.
So, you’ll find heavier snowpack in the north and more mixed conditions down south. If you’re driving between regions, keep in mind that road conditions can flip fast.
Mountain Versus Valley Conditions
The mountains? Way colder, with much more snow. In ranges like the Sawtooths or Bitterroots, Christmas temps can sit between 10°F and 30°F, and storms might dump several inches of snow in a single day. Mountain passes can get icy and tough to cross.
Valleys like Boise and the Snake River Plain stay a little warmer. Snowfall is lighter—just a few inches in December—and roads are usually clearer. Still, freezing fog pops up more in valleys, making things slick even without much snow.
If you’re heading outdoors, the mountains are great for skiing or snowboarding. Valleys are easier for driving and daily errands. That mountain-versus-valley split really stands out in Idaho during Christmas.
Weather Trends in Boise During Christmas
Boise’s weather around Christmas usually means cold days, a shot at light snow, and sometimes rain or dry spells. Temps stay chilly but rarely plunge into the extreme cold. Snow is possible, but you can’t rely on it.
Historical Temperature Data for Boise
In late December, Boise usually gets average highs in the mid-30s °F and lows in the 20s °F. Some years drop into the teens, but it’s rare for Boise to get much colder than 10°F.
The numbers don’t swing much from year to year. Here’s a quick look:
| Date Range | Avg High (°F) | Avg Low (°F) | Notes |
|---|---|---|---|
| Dec 20–26 | 34–37 | 22–25 | Cool days, cold nights |
| Dec 27–31 | 33–36 | 21–24 | Similar pattern, slightly colder |
You’ll want a heavy coat, gloves, and layers for sure. Boise winters aren’t as rough as northern Idaho or the mountains, but they’re still pretty cold.
December brings a few inches of snow total, but it doesn’t always stick around. Boise’s valley spot means it warms up faster than the higher areas nearby.
Chances of a White Christmas in Boise
The odds of a white Christmas in Boise are pretty low compared to the rest of Idaho. On average, the city sees about 0.2 inches of snow on the ground on December 25.
Most Christmas Days in Boise are snow-free, with just bare ground or maybe a few flurries. Every once in a while, you’ll get a big snow—like in 1998, when more than 6 inches fell on Christmas.
Usually, you’re looking at a 20–30% chance of measurable snow on Christmas Day. Snow showers can happen, but it’s rare for it to really pile up in the city.
If you want a better shot at a snowy holiday, you’ll need to head up into the mountains. Boise often gets rain, dry skies, or just a dusting of snow during Christmas week.
Sky Conditions and Daylight
Christmas in Idaho brings mostly cloudy skies and short days. Sunshine gets pretty scarce, and you’ll notice those short daylight hours compared to other times of year.
Cloud Cover and Sunshine Hours
Expect a lot of cloud cover in December. In southern Idaho cities like Boise, you’ll get clear or partly clear skies about 40–45% of the time. Up north in Sandpoint, that drops to 25%. So, most days are pretty cloudy or just straight-up overcast.
Snow on the ground can make things look brighter, but the sun itself is usually hidden. Boise sees about 8 sunny days in December on average, and northern towns get even fewer.
The sun sits low in the sky, even on clear days. Long shadows make things feel dimmer, and you just don’t get much direct light. If you’re planning to be outside, expect it to feel a bit gloomier than other seasons.
Daylight Duration Around Christmas
Daylight hits its shortest stretch during Christmas. Boise and Idaho Falls get about 9 hours of daylight, and Sandpoint up north gets closer to 8.5 hours.
The sun rises after 8:00 a.m. and sets before 5:00 p.m. in most places. So, you’ve got a limited window for travel, skiing, or anything outside.
With such short days, you’ll rely on artificial lights for safety and comfort. If you’re driving, especially in rural or snowy spots, plan for the early sunset. Those long winter nights can feel endless, but honestly, they’re part of Idaho’s holiday charm.
Wind, Humidity, and Fog in December
December in Idaho feels damp and chilly, with light to moderate winds, higher humidity, and plenty of foggy spells. All of this can shape how you plan your activities, drive, or just go about daily life during the holidays.
Typical Wind Speeds and Patterns
Winds in December usually stay light to moderate across Idaho. Most towns, like Emmett and Meridian, see average speeds of 4 to 6 mph. Higher elevations and wide-open valleys can get gustier, especially when storms roll in.
Winds shift with the weather. Before a storm, you’ll notice breezes from the south or southwest, bringing slightly warmer air. After a front moves through, winds swing north or northwest, and colder air rushes in, sometimes with lake-effect or upslope snow.
In valleys such as the Treasure Valley, winds feel calmer than in the passes. That helps lower elevations feel less harsh, though the cold can still bite.
Relative Humidity Levels
Humidity rises in December because cold air just can’t hold as much moisture. Relative humidity in Idaho averages 70–80% this month. Mornings are usually damper, while afternoons dry out a bit as temps climb.
That boost in humidity gives the air a damp chill, even if it’s not actually raining or snowing. It also means you’ll scrape more frost off your car in the morning.
With more humidity and clouds, you’ll see fewer sunny days than in summer or fall. The air feels heavier and colder, especially in shady spots.
Fog Occurrence and Impacts
Fog shows up a lot in December, especially in valleys and near rivers. Cold air settles in low spots, trapping moisture and building up dense fog that can stick around for hours.
You’ll find the thickest fog in the Treasure Valley, around Boise and Meridian, and over in eastern Idaho near Idaho Falls. “Freezing fog” is common here, coating roads, trees, and power lines with tiny ice crystals.
Fog can cut visibility for drivers down to less than a quarter mile, making travel slower and a bit dicey, especially on rural highways. It might even delay flights at smaller airports and put outdoor fun on hold until things clear up.
Travel and Outdoor Considerations
Cold weather, regular snowfall, and short days all shape how you get around and enjoy Idaho at Christmas. Prep for winter driving, plan your activities with safety in mind, and you’ll have a much better time.
Road Conditions and Safety Tips
Snow and ice hit much of Idaho in late December, especially up in the mountain passes and out on those rural highways. Even the big routes like I‑84 and US‑95 sometimes get hit with delays from storms or freezing rain.
If you’re driving into higher elevations, bring chains or traction tires. Roads near Sun Valley or McCall? Yeah, they might require them when the snow really comes down.
I’d toss a small winter kit in your car—blankets, water, snacks, maybe a flashlight. It’s just not worth the risk.
Black ice likes to show up overnight and in those shady spots. Drive slower than usual, leave extra space, and try not to slam the brakes.
Check road condition alerts from the Idaho Transportation Department—they update closures and hazards in real time, which is super helpful.
If you’re renting a car, go for all‑wheel drive or four‑wheel drive if you can. Gas stations get pretty sparse in the more remote parts, so fill up before you head out there.
Best Practices for Holiday Activities
When you think about outdoor recreation around Christmas, you probably picture skiing, snowboarding, snowshoeing, or maybe soaking in hot springs. Resorts like Sun Valley keep the runs groomed, but backcountry trails? Those can be unplowed and much tougher to reach.
I always dress in layers—moisture-wicking stuff close to my skin, something insulated in the middle, and then a waterproof shell on top. That combo keeps me warm, but I don’t end up sweating buckets if I’m moving around a lot.
Don’t forget gloves, a hat, and some thermal socks. Wind chill out there can get brutal, and you’ll want every bit of protection.
Try to plan your outings during the daylight, since December sunsets sneak up fast. If you might be out late, just toss a headlamp in your bag.
For snow play with kids, I’d stick to designated sledding hills or well-maintained parks. It’s safer, and you won’t have to worry as much about hidden rocks or branches.
If you’re heading to hot springs, watch your step on those icy paths. I wouldn’t stay in the water too long if it’s seriously cold outside.
Before you go anywhere, check local advisories. Avalanche warnings and trail closures happen pretty often in the mountains, so it’s better to know ahead of time.