Yellowstone Weather: Forecasts, Climate, and Current Conditions

By Victoria Boissonade · Data: National Park Service · ← Complete guide Yellowstone

Yellowstone sits at an average elevation of more than 7,200 feet, so the park has an almost mountain climate, and the weather can change dramatically within a few hours. In short, summers are short and relatively cool (July rarely gets above 73°F), winters are long and intense (overnight temperatures often drop below 0°F), and spring and fall can be unpredictable. It can snow in any month of the year. That's not just a figure of speech. We experienced it in June, standing in fresh snow at Dunraven Pass while the rest of the group had been wearing T-shirts two days earlier.

Yellowstone Climate Month by Month

The table below summarizes climate normals for the Old Faithful area (about 7,400 feet), in the heart of the park. Precipitation includes snow converted to its water equivalent.

Precipitation peaks in May and June, when snowmelt combines with the first convective thunderstorms. July and August are the driest and sunniest months, but afternoon thunderstorms remain almost daily.

The Climate Season by Season

Winter (December - March)

This is Yellowstone at its wildest: landscapes blanketed in snow, steaming geysers against a white backdrop, and bison digging through the ice crust to reach the grass. Overnight temperatures routinely fall below 0°F and can approach -22°F in lower areas. Nearly all roads are closed to wheeled vehicles. Most access is by snowmobile or snowcoach through the West Entrance, which is open to tracked vehicles from December 15 through March 15. Mammoth Hot Springs is the only area that remains accessible by car year-round. For practical access information, see the park access guide.

Spring (April - May)

Spring is the most deceptive season. A sunny 54°F day can end with a snowstorm. The West Entrance generally reopens to wheeled vehicles on the third Friday in April, depending on current weather conditions. Snowmelt swells the rivers and leaves many trails muddy or temporarily flooded. This is also when grizzly bears and black bears emerge, hungry after hibernation. For practical safety advice, see the Yellowstone wildlife guide.

Summer (June - August)

July and August bring the peak season. Daytime temperatures can climb above 70°F, and sometimes higher in the lower valleys, but nights remain cool at around 45 to 50°F. The biggest summer hazard is the afternoon thunderstorm: it can form quickly, bring frequent lightning, and produce hail. When we visited in July, our morning hike ended beneath a clear blue sky at 11 a.m. By 3 p.m., the sky was black. Plan mountain outings for the morning and leave exposed ridges before 1 p.m.

Fall (September - October)

September is a favorite with regular visitors: daytime temperatures are still mild at 59 to 63°F, morning mist hangs over the hydrothermal features, and the elk rut gets underway with plenty of bugling. Crowds drop sharply after the American Labor Day holiday, the first Monday in September. In October, snow settles in for the season at higher elevations, and some entrances gradually close to wheeled vehicles.

Is Yellowstone Cold or Warm? Records and Extremes

Cold, yes, and without compromise. The NPS states it clearly: winter lows regularly fall below 0°F, not just during exceptional cold snaps. Snow has been recorded every month of the year on the plateau. At the other extreme, some summer days have topped 86°F in the lower valleys, exposing visitors to heat-related illness and altitude-accelerated dehydration.

What to Wear by Season

The basic rule from January through December is simple: wear layers.

• Summer (June-August): Technical T-shirt and a lightweight fleece for the morning, a waterproof windbreaker for afternoon storms, and waterproof hiking shoes. SPF 50 sunscreen is essential at this elevation.
• Spring / fall: A warm midlayer, such as fleece or a lightweight down jacket, a waterproof jacket, gloves, and a beanie. April and October mornings regularly reach 32°F or below.
• Winter: An expedition-weight down jacket rated to at least 0°F, a merino wool base layer, insulated pants, ski gloves, and a balaclava. Waterproof winter boots with lugged soles replace standard hiking shoes.

In every season, carry at least 2 liters of water per person for each half-day of hiking, plus one more layer than you think you'll need.

Alerts and Conditions to Watch

Lightning (June-August): A major risk on ridges and near bodies of water. Descend as soon as cumulus clouds appear, and never take shelter under an isolated tree. The National Weather Service (NWS) issues Hazardous Weather alerts specific to the area.

Road closures (spring and fall): The park's five entrances don't open and close at the same time. Before you hit the road, check real-time access conditions on the official NPS website. Opening dates and conditions for each Yellowstone entrance are detailed in the park access guide.

Hydrothermal activity: Steam from geysers and hot springs can reduce visibility locally and create unstable ground. Stay on marked boardwalks. The ground can collapse without warning outside developed areas.

Frequently Asked Questions