August weather forecastYellowstone National Park, WY

August
Weather in August
August displays temperatures similar to those of July, sustaining the summer's warmth in Yellowstone National Park. In spite of the heat and scanty 1.6" (41mm) of rain, August days remain relatively crisp. The park's diverse wildlife have adapted to cope with these conditions, offering exemplary viewing opportunities. Wildfires, although infrequent, are a potential weather-related risk. Activities such as camping and hiking remain popular thanks to the long sunny days.Temperature
A minor adjustment in Yellowstone National Park's average high-temperature is noted with the start of August, touching a still pleasant 71.4°F (21.9°C) from July's 71.6°F (22°C). Marked by a significant temperature drop from daytime highs, the average nighttime temperature lowers to a cold 39.9°F (4.4°C) throughout August.Rainfall
In August, the rain falls for 10.8 days. Throughout August, 1.61" (41mm) of precipitation is accumulated. In Yellowstone National Park, during the entire year, the rain falls for 151 days and collects up to 20.91" (531mm) of precipitation.Snowfall
In Yellowstone National Park, Wyoming, snow does not fall in July and August.Daylight
In August, the average length of the day is 13h and 59min.On the first day of August, sunrise is at 6:10 am and sunset at 8:46 pm. On the last day of the month, sunrise is at 6:44 am and sunset at 7:59 pm MDT.
Sunshine
In Yellowstone National Park, the average sunshine in August is 10h.UV index
In Yellowstone National Park, the average daily maximum UV index in August is 8. A UV Index value of 8 to 10 symbolizes a very high health vulnerability from unprotected exposure to Sun's UV rays for the average person.Note: The maximum daily UV index of 8 in August interprets into the following recommendations:
Being unprotected puts skin and eyes at risk of rapid damage. Always be safe. Avoid direct Sun exposure and stay in the shade between 10 a.m. and 4 p.m., a time when UV radiation is most intense, noting that not all shade structures offer full protection. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in August
Yellowstone National Park, WY
- Average high temperature in August: 71.4°F
The warmest month (with the highest average high temperature) is July (71.6°F).
The month with the lowest average high temperature is December (24.3°F).
- Average low temperature in August: 39.9°F
The month with the highest average low temperature is July (41.6°F).
The coldest months (with the lowest average low temperature) are January and February (1.2°F).
Average rainfall in August
Yellowstone National Park, WY
- Average rainfall in August: 1.6"
The wettest month (with the highest rainfall) is May (2.5").
The driest month (with the least rainfall) is October (1.2").
Average rainfall days in August
Yellowstone National Park, WY
- Average rainfall days in August: 10.8 days
The month with the highest number of rainy days is January (16.8 days).
The month with the least rainy days is October (8.8 days).
Average snowfall in August
Yellowstone National Park, WY
- Average snowfall in August: 0"
The month with the highest snowfall is January (34.3").
The months with the least snowfall are July and August (0").
Average snowfall days in August
Yellowstone National Park, WY
- Average snowfall days in August: 0 days
The month with the highest number of snowfall days is January (16.2 days).
The months with the least snowfall days are July and August (0 days).
Average daylight in August /
Average sunshine in August
Yellowstone National Park, WY
- Average daylight in August: 14h and 0min
The month with the longest days is June (Average daylight: 15h and 30min).
The month with the shortest days is December (Average daylight: 8h and 54min).
- Average sunshine in August: 10h
The month with the most sunshine is July (Average sunshine: 11h).
The month with the least sunshine is December (Average sunshine: 4h).
Average UV index in August
Yellowstone National Park, WY
- Average UV index in August: 8
The month with the highest UV index is July (UV index 10).
The months with the lowest UV index are January and December (UV index 1).





