Weather

People like to joke that the only seasons in Yellowstone are July, August, and Winter.  And while it isn’t uncommon at all for it to snow even in July or August, there’s a lot more variety within the seasons than that statement might suggest.  Historical data is provided below, along with information about weather monitoring systems in the park.

Summer: Daytime temperatures are often in the 70s (25C) and occasionally in the 80s (30C) in lower elevations. It’s not unheard of for daytime temps to reach into the 90s during some of the warmer summers.  Nights are usually cool (in the 30s and 40s F) and temperatures may drop below freezing at higher elevations. Thunderstorms are common in the afternoons, and it isn’t terribly uncommon for it to snow lightly at some of the higher elevations.

Winter: Temperatures often range from zero to 20F (-20 to -5C) throughout the day. Overnight temperatures well below zero are common. The record low temperature is -66F (-54C). Snowfall is highly variable, with the southern portions of the park getting more snow than the northern portions. While the average is 150 inches per year, it is not uncommon for higher elevations to get twice that amount. See the Winter Daily Reports for specific conditions.

Spring & Fall: Daytime temperatures range from the 30s to the 60s (0 to 20C) with overnight lows in the teens to single digits (-5 to -20C). Snow is common in the Spring and Fall with regular accumulations of 12″ in a 24 hour period. At any time of year, be prepared for sudden changes.

Unpredictability, more than anything else, characterizes Yellowstone’s weather. Always be equipped with a wide range of clothing options. Be sure to bring a warm jacket and rain gear even in the summer, and dress in layers at all times of the year.  It tends to stay pretty windy in certain areas of the park as well, particularly at the higher elevations.

Yellowstone’s Current Weather Information & Forecasts

Yellowstone’s Historical Weather Information

The following tables provide information on historical averages at various locations throughout the park.  The data are based on readings taken from 1948 through 2005.  You can see the tremendous variation in temperatures and precipitation totals among the different areas of the park. 1

Mammoth
JFMAMJJASOND
Avg Max29.534.040.149.660.469.580.278.768.055.538.830.6
Avg Min10.212.917.826.034.241.247.045.437.429.419.412.2
Avg T Prec1.050.701.051.181.942.071.431.341.231.001.020.96
Avg T Snow14.69.712.66.01.50.2000.53.39.513.0
Avg S Dpth885100000024
Lamar Ranger Station
JFMAMJJASOND
Avg Max24.630.737.548.760.668.478.276.668.055.837.426.8
Avg Min0.84.29.120.027.233.336.334.227.120.711.11.9
Avg T Prec0.970.630.670.901.452.051.401.361.450.940.790.89
Avg T Snow20.715.013.48.51.90.3001.94.010.917.6
Avg S Dpth121513400000026
Tower Falls
JFMAMJJASOND
Avg Max26.933.341.650.461.369.779.478.968.955.837.627.6
Avg Min0.13.410.520.028.133.837.735.828.320.710.81.8
Avg T Prec1.330.881.041.201.932.171.641.451.391.131.131.30
Avg T Snow21.613.513.58.21.90.3000.83.612.420.1
Avg S Dpth1720196000000310
Lake Ranger Station
JFMAMJJASOND
Avg Max23.028.034.642.852.361.271.571.061.449.233.925.3
Avg Min-1.7-1.03.614.524.932.838.437.329.421.811.32.6
Avg T Prec2.001.481.641.571.942.211.531.671.611.331.641.74
Avg T Snow35.125.226.015.55.900.8000.101.407.7022.930.2
Avg S Dpth30374133900001718
South Entrance/Snake River
JFMAMJJASOND
Avg Max26.031.037.646.956.967.377.376.466.652.835.926.5
Avg Min0.30.68.118.527.133.437.535.327.119.99.80.5
Avg T Prec4.223.122.772.312.622.411.581.611.692.083.214.29
Avg T Snow55.745.335.818.96.40.9000.79.537.058.5
Avg S Dpth435557421000001928
Old Faithful Ranger Station
JFMAMJJASOND
Avg Max28.232.039.146.655.364.774.473.664.150.834.827.1
Avg Min0.20.79.318.427.834.439.036.528.820.88.4-0.6
Avg T Prec2.341.842.202.062.662.311.671.531.521.612.262.43
Avg T Snow38.632.230.120.28.11.4001.78.230.541.3
Avg S Dpth29363723400001720

Weather Monitoring Systems in Yellowstone

You can find out more about the devices and systems used to monitor various aspects of the weather on the Weather/Seismic Monitoring Systems page.