Yellowstone National Park Weather in September
With daytime temperatures of 17°C (63°F) and nighttime lows of 0°C (32°F), September in Yellowstone National Park brings moderate temperatures during the day. Some rainfall is to be expected during the month.
Rainfall in Yellowstone National Park in September
Records from the past 30 years suggest around 10 days of rain, with 40 mm (1.6 in) average for the month. A fairly balanced picture this month, some wet days but nothing too extreme in terms of intensity.
Temperature in Yellowstone National Park in September
Temperatures in Yellowstone National Park in September top out at 17°C (63°F) and drop to 0°C (32°F) overnight. The difference between afternoon and evening temperatures is usually noticeable. At 0°C (32°F) overnight, it gets properly cold after dark. On the bright side, cold nights tend to make for excellent sleeping conditions.Should you favor a climate that's both dry and comfortably warm, July and August typically offer the most agreeable circumstances. If you're seeking pleasant, dry and sunny weather somewhere else in the world, our weather planner can help you explore other options.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Yellowstone National Park's climate page.
Yellowstone National Park Temperature in September
Min Temperature
0°C (32°F)
Max Temperature
17°C (63°F)
Chance of Rain
33%
Precipitation
40 mm (1.6 in)
Rainy days
10 days
Daily Historical Temperatures
45-year average (1976-2025)
Based on our historical records, temperatures in Yellowstone National Park typically drop from around 20°C (68°F) at the start of September to approximately 14°C (57°F) by the end. Nights are cold, with lows typically ranging from -2°C (28°F) to 3°C (37°F).
Average temperatures in September
Daily Historical Precipitation
45-year average (1976-2025)
Average daily rainfall for each day of the month based on long-term records.
Average precipitation in September
Historical weather for Yellowstone National Park in September
Browse day-by-day weather records for Yellowstone National Park spanning 51 years. Select any month and year to see actual temperatures, rainfall, and conditions recorded on each day.
Yellowstone National Park historical weather extremes in September
Our historical data for Yellowstone National Park spans 2001 to 2025, revealing these weather extremes.
- Yellowstone National Park recorded its highest September temperature of 28°C (82°F) on September 5, 2020.
- Yellowstone National Park registered its coldest September night on September 12, 2014, with temperatures dropping to -8°C (18°F).
Best Places in the United States of America in September
Find out more about the weather in the United States of America and which places have the best travel conditions in this month. See all of the United States of America in September →
perfect weather
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unpleasant
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What to Wear in Yellowstone National Park in September
Comfortable temperatures call for an easy wardrobe in September. Pack summer basics like t-shirts and shorts, but include a light jacket for cooler moments. A pair of comfortable walking shoes is essential. Wet weather is likely, so pack waterproof gear for multiple rainy days.What To Do in Yellowstone National Park in September
We rated the following activities from 1 (least suitable) to 10 (best) to do.
Check the conditions for any month of the year.
For a detailed overview over the year and the best time to visit the United States of America, check out our Yellowstone National Park's climate page.
See the full Yellowstone National Park climate overview or explore weather in the United States of America.
