Yellowstone National Park is an immense wilderness area spanning over 3,400 square miles, predominantly located in the northwest corner of Wyoming, with small sections extending into Montana and Idaho. This natural area experiences a highly variable, subarctic-influenced mountain climate. Weather conditions can change rapidly and differ significantly from one region to another. Yellowstone’s climate is largely defined by its high-altitude setting, resulting in a generally cool temperate and continental environment throughout the year.
Defining the Seasons
The four seasons in Yellowstone are marked by distinct temperature profiles, though weather remains unpredictable year-round. Summer, which typically runs from mid-June to early September, brings the warmest and driest conditions. Daytime temperatures at lower elevations often reach 70°F, occasionally climbing to 80°F, but nights are consistently cool, frequently dropping to the 30s or 40s°F. This season is prone to sudden, intense afternoon thunderstorms, especially in June.
Winter is long and severe, generally lasting from November into April, and is characterized by extremely low temperatures. During the day, temperatures commonly range from 0°F to 20°F, with sub-zero readings frequent at night and in higher-elevation areas. The park’s record low was -66°F.
Spring (March to early June) and Fall (September to November) are transitional periods defined by high unpredictability. Daytime temperatures can swing widely, generally from 30°F to 60°F in the spring and 50°F to 70°F in the early fall. Overnight lows regularly drop into the teens or single digits, and snow is a common occurrence during both seasons.
Geographic and Altitude Factors
The primary driver of Yellowstone’s unique climate is its high elevation, as the park sits on the Yellowstone Plateau, with an average elevation of 8,000 feet above sea level. This great height above sea level is the reason for the consistently cold temperatures and the high degree of weather variability. The elevation within the park ranges dramatically, from a low of 5,282 feet along Reese Creek to a high of 11,358 feet at Eagle Peak.
The plateau is surrounded by numerous mountain ranges belonging to the Middle Rocky Mountains, such as the Gallatin, Absaroka, and Teton ranges. These mountain barriers influence weather patterns by affecting the movement of air masses across the region. For instance, the topography can create a rain shadow effect, resulting in the northern range being one of the driest areas in the park.
Within this high-altitude environment, microclimates exist, adding to the complexity of the weather. The extensive network of geothermal features, including geysers and hot springs, creates localized pockets of warmer ground and air. These areas, such as the Upper Geyser Basin, can experience slightly milder conditions compared to the surrounding high-elevation terrain.
Precipitation and Snowfall Dynamics
Moisture in Yellowstone is highly dependent on location and elevation, with annual precipitation ranging from about 10 inches in the drier northern areas to 80 inches in the southwestern corner. The vast majority of this moisture arrives as snow, defining the park’s winter and shaping its ecology. On average, the park receives about 150 inches of snow annually, though higher elevations can receive between 200 and 400 inches.
The snowpack is a defining feature of the park’s hydrology, often accumulating from early autumn and persisting well into April or May. At higher elevations, significant snowpack can remain until June, affecting the opening of many park roads and the accessibility of trails. Areas on the western slopes of the surrounding mountains tend to receive the highest accumulation due to orographic lifting of moist air masses.
This heavy snowfall plays a substantial role in the regional water supply, acting as a massive, slow-release reservoir. The meltwater from the deep snowpack feeds the headwaters of several major rivers, including the Yellowstone River. The timing and volume of this spring melt are important, as rapid thawing combined with heavy rain can lead to significant flooding events.