Planning to celebrate St. Patrick’s Day in Montana? You’ll want to brace yourself for a late-winter chill, but there’s always that faint hint of spring in the air.
Daytime temperatures usually hover anywhere from the upper 30s to the mid-40s Fahrenheit, though it gets colder up in the mountains and a bit milder out on the plains.
At night, temps often dip below freezing, so you’ll definitely want to dress in layers.
Snow can still show up in March, especially in western and higher-elevation spots.
Rain starts to become more common in the valleys and eastern Montana.
A passing storm might leave roads slick and bring sudden weather shifts, but you’ll also get plenty of clear, sunny spells.
March, honestly, might be Montana’s most unpredictable month.
Knowing what kind of weather might roll in helps you squeeze the most out of parades, festivals, or outdoor gatherings.
Missoula, Billings, Bozeman—wherever you end up, St. Patrick’s Day weather in Montana always brings a bit of everything.
Sometimes brisk, sometimes pleasant, but almost never boring.
Typical Temperature Ranges in March
Montana’s March weather bounces between winter’s chill and early spring warmth.
Temps can swing a lot depending on where you are, what time it is, and the date itself.
Highs and Lows on St. Patrick’s Day
On St. Patrick’s Day, high temperatures usually land in the low 40s °F in the north and west, and can get close to 50 °F in the south and east.
Lows often slide down into the teens and 20s °F, especially up in the mountains.
Take Billings for example—it often hits highs around 49 °F and lows near 27 °F.
Bozeman tends to run cooler, with highs in the mid-40s and lows in the low 20s.
Mountain towns like West Yellowstone can be downright cold, sometimes dropping near 10 °F at night.
You really notice how location changes your experience.
Planning to be outside?
You’ll want to prep for chilly mornings but also milder afternoons.
Layers are key, since Montana weather loves to keep you guessing.
Temperature Trends in Recent Years
March 17 in Montana is kind of a wild card.
Some years, highs get stuck in the 30s °F, while other years, you’ll see them climb into the 50s °F.
Nights usually stay below freezing, but in milder years, mornings start in the upper 20s °F.
Weather records show both late-winter cold and early-spring warmth can show up on this date.
Across the U.S., extremes have ranged from below zero to well into the 80s °F, and Montana sees its share of swings too.
You just can’t count on a steady pattern.
Best to check the forecast, especially if you’re traveling or planning something outdoors.
Daytime Versus Nighttime Conditions
Daytime in mid-March usually feels cool but manageable, with highs in the 40s °F.
If the sun’s out, afternoons can feel warmer, especially down in the valleys.
Once night falls, things change fast.
Lows drop into the teens or 20s °F, and mountain spots can dip into the single digits.
That big day-to-night gap means you need to prep for cold evenings, even if the afternoon felt mild.
If you’re staying out late or camping, expect freezing temps after dark.
Regional Weather Differences Across Montana
Mid-March weather in Montana shifts a lot depending on where you are.
Elevation, the lay of the land, and how close you are to the mountains all matter when it comes to snow, rain, and temperature swings.
Western Montana Climate Patterns
Western Montana sits in the mountains, so you can count on cooler temps and unsettled weather in mid-March.
Daytime highs often land in the 30s and 40s °F, and overnight lows dip well below freezing.
Snow falls pretty often, and even the valleys can see a few inches this time of year.
Moisture from the Pacific moves into the Rockies, mixing things up with snow, rain, and sometimes sleet.
Missoula and Helena might get a rain-snow blend, while higher spots like the Bitterroot and Absaroka ranges get heavier snow.
Travel gets trickier here thanks to icy passes and gusty winds.
Roads like I‑90 or US‑93 can turn slick fast.
If you’re planning to get outside, expect the skies to change and be ready for surprise precipitation.
Eastern Montana Weather Characteristics
Eastern Montana feels pretty different.
The land’s flatter, the air’s drier, and you’ll usually see less snow and more sunshine in March.
Daytime highs often reach the 40s or even 50s °F, but nights still dip below freezing.
This side of the state doesn’t get as much mountain-driven snowfall, so weather stays more stable.
You might get a light rain or quick snow shower, but dry spells are common.
You’ll probably notice bigger temperature swings here than in the west.
Warm afternoons can flip to chilly evenings, so don’t skip the layers.
Billings and Glasgow often feel milder than towns out west, making travel and outdoor plans a bit easier.
Precipitation and Snowfall Probabilities
Around St. Patrick’s Day in Montana, you’ll get a mix of rain and snow, depending on where you are and the elevation.
Western valleys see more light rain, while the higher spots and mountain passes still pick up measurable snow.
Mid-March usually brings unsettled weather, but not crazy amounts of precipitation.
Rain and Snow Mix Frequency
In western Montana valleys, mid-March daytime highs usually run from the low 40s to upper 50s °F.
At those temps, you’ll often get rain during the day, but it can flip to snow overnight when it cools off.
On average, March brings 8–12 days with precipitation in a lot of Montana cities.
For St. Patrick’s Day itself, the chance of any measurable precipitation is about 30%, with light rain a bit more likely than snow in the lower spots.
Rain-snow transitions pop up most in Missoula, Helena, and Great Falls, where temps hover near freezing.
Travelers should prep for wet roads in the afternoon and slick surfaces by morning if the temps drop fast.
Snowfall in Mountain Passes
Mountain passes like Lookout Pass and Lolo Pass in western Montana still see snow on St. Patrick’s Day.
Average March snowfall in these areas often tops 20 inches, and a single storm can drop several inches in one go.
Above 5,000 feet, snow rules in mid-March.
While valleys might get cold rain, the passes can get heavy snow that makes travel tough.
Slush and ice are common, especially overnight or in shady spots.
If you’re driving mountain routes, bring chains or be ready for winter driving.
Snow showers can show up fast, even if nearby valleys just see rain or clouds.
Historical Precipitation Data
Long-term records show Montana cities average 0.03 to 0.05 inches of precipitation on March 17.
That’s not a lot, but some years have brought over 0.5 inches of rain or several inches of snow on the holiday.
Over the past century, measurable precipitation has hit about 1 in 3 St. Patrick’s Days in Montana.
Snow’s less common in the valleys, averaging 0.1 to 0.3 inches, but it can pile up higher in the mountains.
You really can’t predict what you’ll get.
Some years are dry and sunny, others bring unsettled skies with light rain or snow showers.
Mid-March is just a transition period—winter and spring both show up.
Wind and Other Weather Factors
Mid-March in Montana often feels unsettled.
Brisk winds and shifting skies are the norm, so some days feel bright and others stay cloudy.
All of this shapes what St. Patrick’s Day feels like outside, whether you’re walking downtown or driving through open country.
Wind Patterns in March
March winds in Montana blow stronger than in summer or fall.
The shift from winter to spring brings pressure changes, so you’ll feel more gusts.
On St. Patrick’s Day, steady breezes sweep the plains, and mountain passes get sharper gusts.
Eastern towns like Sidney often get moderate winds, while Livingston is famous for higher averages—sometimes over 15 mph.
Open valleys can feel even gustier, especially when a cold front rolls in.
Planning something outdoors?
Wind’s almost always a factor.
Lightweight decorations might not last, and parades or gatherings can feel colder than the numbers say.
Dress in layers and pick wind-resistant gear if you want to stay comfortable.
Cloud Cover and Sunshine Levels
Montana’s March skies are a mixed bag—sunny breaks, then long stretches of cloud.
Around St. Patrick’s Day, you get about 12 hours of daylight, which feels like a treat after winter.
Sunshine, though, sometimes hides behind lingering storm systems.
Cloud cover depends on where you are.
Eastern Montana sees clearer skies, while the mountains hold onto more clouds.
When the sun finally breaks through, it feels stronger thanks to the higher solar angle.
You can expect 4 to 6 hours of sunshine on a typical March day.
That’s enough to make afternoons feel decent, even if temps stay cool.
If you’re outside, sunglasses and sunscreen aren’t a bad idea—UV ramps up fast in spring.
Weather Impacts on St. Patrick’s Day Events
Montana’s weather in mid-March can swing from winter to spring in a single day.
That affects how you celebrate outside and how safely you can get between towns for parades or other events.
Outdoor Celebrations and Parades
Heading to a St. Patrick’s Day parade in Western Montana?
You might get rain or snow, depending on elevation.
Missoula’s valley often sees light rain, but higher terrain can get snow.
Weather changes fast, so dressing in layers is your best bet.
Parade organizers usually keep events going, even with light precipitation.
Wet streets can make standing around less fun, though.
Waterproof boots and a rain jacket are a good call if showers pop up.
Temps swing a lot too.
Afternoon highs might feel mild, but mornings are often chilly.
A hat and gloves help if you’re showing up early.
Wind can also make it feel colder than the forecast says.
Key tips for outdoor events:
- Check hourly forecasts before heading out
- Bring waterproof clothing and footwear
- Plan for both sun and snow on the same day
Travel Considerations
Traveling across Montana on St. Patrick’s Day?
You’ll probably deal with changing road conditions.
Rain in the valleys can turn to snow or slush in the passes.
The drive from Missoula to Butte, for example, can switch from wet roads to slick ones in just a few miles.
If you’re driving to a parade or family gathering, give yourself extra time.
It’s smart to keep a small winter kit in your car—think blanket, gloves, windshield scraper—even in mid-March.
Visibility drops with fog, snow showers, or even graupel (those soft snow pellets).
Slowing down and leaving more space between cars keeps you safer in those conditions.
For longer trips, check Montana Department of Transportation updates before leaving.
They’ll have the latest on pass closures, chain laws, or icy patches.
Travel checklist:
- Check road reports before you go
- Pack winter gear even if it looks mild
- Give yourself extra time for mountain drives
Preparing for Variable March Weather
Montana’s mid-March weather can flip quickly.
You might get a mild afternoon, then a sudden snow shower just a few hours later.
You really need to plan for both winter and spring—temps and precipitation can change more than once in a single day.
What to Pack for St. Patrick’s Day in Montana
Pack clothing that you can layer up or down. Start with a warm base layer. Add an insulating mid-layer like fleece or wool, then toss on a waterproof outer shell if you need it.
As the day goes on, you’ll probably want to adjust your layers. Temperatures can climb in the afternoon, but drop fast when the sun sets.
Don’t forget about your feet. Insulated boots with decent traction really help if you run into snow or slush. If things are just wet and not icy, lighter waterproof shoes do the trick.
Bring along warm socks, gloves, and a hat. Wind chill can turn a mild day into something that feels way colder.
Heading to outdoor events or a parade? Pack a compact umbrella or a light rain jacket. March in Montana loves to surprise you with light rain or wet snow. Staying dry just makes everything better.
Sunglasses might seem optional, but they’re actually pretty useful. Sunlight bouncing off snow can be surprisingly harsh.
Throw a small daypack over your shoulder for extra layers, snacks, and water. You’ll be glad you did if the weather suddenly shifts.
Staying Updated With Local Forecasts
Check the National Weather Service or trusted local stations for the most reliable forecasts. Montana’s wild terrain creates all sorts of microclimates, so weather in one valley can feel totally different from what’s happening in the nearby mountains.
A forecast for Billings might not even come close to what you’ll run into in Bozeman or Helena. Honestly, it pays to stay skeptical.
Try to monitor updates every day during the week leading up to St. Patrick’s Day. March weather systems love to surprise us, sometimes throwing snowstorms, rain, or strong winds with barely any warning.
Use mobile weather apps with location tracking so you’ll get alerts as conditions shift. Most apps break things down by the hour, making it easier to plan outdoor stuff around possible rain or sudden temperature drops.
If you’re driving, check the Montana Department of Transportation road reports before you go. Roads can ice up overnight, even if things felt mild just a day earlier.
Paying attention to travel conditions can save you from delays or unpleasant surprises.