Yellowstone National Park in September
Yellowstone National Park · crowd + weather almanac
September crowd level
busy
about 781,000 visits in a
typical September
The 4th-busiest month of the year ·
median of 2016–2025 official NPS counts
September is the 4th-busiest month of the year at Yellowstone National Park: about 781,000 recreation visits in a typical September (18% of the year's traffic, and 81% of what the peak month, July, sees). This is a busy month, though short of the summer-peak crush. Weather-wise, September days at the Yellowstone Park Mammoth, WY station typically top out around 69°F with nights near 39°F, and about 1.2 inches of precipitation falls over the month.
- Typical September: 780,784 recreation visits (median 2016–2025); the range across those years ran 567,587 (2022) to 882,078 (2021).
- Busier than 8 of the other 11 months.
- 1991–2020 September normals at Yellowstone Park Mammoth, WY: high 69°F, low 39°F, 1.21 in precipitation, 0.6 in snow.
September weather (1991–2020 normals)
| Typical daytime high | 69°F |
|---|---|
| Typical overnight low | 39°F |
| Precipitation (monthly normal) | 1.21 in |
| Snowfall (monthly normal) | 0.6 in |
| Measured at | Yellowstone Park Mammoth, WY (USC00489905), 0.2 mi from the park reference point, elev. 6,195 ft |
Every month at Yellowstone
| Month | Typical visits | Crowds | High / Low | Precip |
|---|---|---|---|---|
| January | 34,617 | quietest stretch | 31°F / 12°F | 0.9 in |
| February | 39,388 | quietest stretch | 34°F / 12°F | 0.8 in |
| March | 31,280 | quietest stretch | 42°F / 19°F | 1.1 in |
| April | 63,380 | quietest stretch | 50°F / 26°F | 1.4 in |
| May | 450,568 | moderate | 60°F / 35°F | 1.8 in |
| June | 824,600 | busiest stretch | 70°F / 42°F | 1.9 in |
| July | 966,048 | busiest stretch | 81°F / 48°F | 1.3 in |
| August | 857,324 | busiest stretch | 80°F / 46°F | 1.1 in |
| September | 780,784 | busy | 69°F / 39°F | 1.2 in |
| October | 270,565 | quiet | 54°F / 29°F | 1.3 in |
| November | 20,621 | quietest stretch | 39°F / 19°F | 1.1 in |
| December | 29,526 | quietest stretch | 30°F / 12°F | 0.9 in |