Yellowstone National Park Weather by Month: What to Expect Year-Round

Monthly Weather & Conditions

These temperatures and precipitation totals are recorded at Yellowstone's weather station near Mammoth Hot Springs. Expect considerably colder conditions at higher elevations throughout the park.

Summer (June–August): Warmest & Most Crowded

June through August are the only months when most park roads are open and all services operate normally. Daytime highs range from 70°F (June) to 80°F (July–August), but nights still drop to 45–47°F. Snowfall is virtually zero, though thunderstorms are common in afternoons and early evenings—they're typically brief, drop temperatures sharply, and pass quickly.

Crowds peak in July and August. Campgrounds fill early, lodging books months ahead, and entrance stations have consistent lines. June and September shoulder into summer and offer the same road access with noticeably fewer visitors. Prepare for rapid temperature swings: bring a warm jacket and rain gear even on clear mornings. Visitors often underestimate nighttime cold, especially after a thunderstorm.

Spring (April–May): Roads Reopening, Unpredictable Weather

Spring is the park's most unpredictable season. April highs hover around 49°F with lows near freezing; May warms to 60°F daytime but still sees 1.5 inches of snow on average. Roads reopen on a staggered schedule depending on snowmelt: the West Entrance typically opens the third Friday in April, while the East and South entrances wait until the first or second Friday in May. Dates vary by 1–2 weeks year to year.

Services resume gradually as roads open. Campgrounds and lodging reopen incrementally through May. Expect muddy trails, occasional road closures from late-spring storms, and construction or maintenance work as the park transitions from winter. Visitation increases steadily through May but remains well below summer levels. Pack layers and waterproof gear—a bright morning can turn into snow or rain by afternoon.

Fall (September–October): Cooling, Lower Crowds, Early Snow

September is an excellent shoulder month. Daytime highs average 68°F, nights dip to 37°F, and precipitation remains light. Most park roads stay open through September and into October, though overnight temperatures can frost lakes and higher elevations. October brings rapid cooling—highs drop to 56°F and snow increases to 3.7 inches. Dunraven Pass and other high-elevation roads close when snow accumulates.

Crowds drop significantly after Labor Day compared to summer, though weekends remain busy. Clear skies and crisp air make wildlife viewing easier. Fall color is minimal (Yellowstone is mostly conifer forest), but high-country views become dramatic as aspen turn. Campgrounds and lodging availability improves. Prepare for freezing nights in October and the possibility of fresh snow; bring cold-weather layers and rain gear.

Winter (November–March): Limited Access, Snowmobile-Only Interior

Winter transforms Yellowstone into a snowfield. November sees the first heavy snow (9 inches average); by January, monthly snowfall averages 14.5 inches and daytime highs barely reach 29°F. Nighttime lows frequently drop below 0°F. Most park roads close by mid-November except the North Entrance near Gardiner, Montana, which remains open to wheeled vehicles year-round, providing access only to Mammoth Hot Springs.

Access to the rest of the park requires a snowmobile or heated snowcoach tour. Snowmobile season typically runs December 15 through mid-March at the West, East, and South entrances. Winter visitation is minimal—mostly backcountry skiers, snowmobile enthusiasts, and organized tour groups. The trade-off for extreme cold and limited access is solitude, fewer wildlife crowds, and spectacular snow-covered geothermal features.

Road Access Windows & Current Delays

Entrance reopenings depend entirely on snowmelt and are weather-dependent. The North Entrance (Gardiner, Montana) is the only entry open year-round to wheeled vehicles. The West Entrance typically reopens the third Friday in April; the East and South entrances follow in May (first or second Friday, respectively). All entrances close to wheeled vehicles by early November. Snowmobile/snowcoach access operates December 15 through mid-March at West, East, and South entrances.

The Beartooth Highway (US-212) between Red Lodge and Cooke City closes November through April each year. Within the park, Dunraven Pass (between Mammoth and Norris) typically closes by late October due to snow and doesn't reopen until mid-April. Check the NPS website for current status before visiting, especially during spring and fall transitions, as one winter storm can delay an opening by 1–3 weeks. The Gardner River High Bridge currently experiences single-lane traffic and up to 15-minute delays from April through late October 2026.

When to Visit: Practical Recommendations

**July–August** guarantee full road access and warm daytime weather (70–80°F), but expect peak crowds, booked accommodations, and higher prices. **June and September** offer the same road access with 20–30% fewer visitors and slightly cooler temperatures (60–70°F)—ideal if you can be flexible. **May and October** are true shoulder seasons: most roads are open, but weather is unpredictable (possible snow, rain, or frost), crowds are low, and lodging is easier to find.

**April** sees roads reopening but access remains incomplete and unpredictable; use this month only if you're comfortable with potential closures. **November–March** is winter-only territory: the North Entrance stays open, but access to geysers and lakes requires snowmobiles or tours. Choose this if you specifically want winter solitude, backcountry skiing, or snowmobile touring. Arrive with serious cold-weather gear—highs barely reach 30°F and lows drop well below freezing.