Weather on September 18 at Yellowstone
Yellowstone National Park
Based on 55 years of data from Jackson, WY
Elevation Note: Yellowstone sits at 7,350 ft. Expect temperatures 26°F cooler than the data shown below, which comes from Jackson, WY at a lower elevation.
Planning Your Visit
September 18th in Yellowstone National Park (via Jackson, WY) typically brings mild fall weather, with average highs around 69°F and lows near 32°F — a 37°F daily swing. Over 55 years of records, the warmest September 18th was in 2004 (69°F average), while the coldest was 1971 (34°F) — a 35°F range across recorded history. Rain or other precipitation has occurred on about 25% of September 18th dates historically, with the wettest September 18th recording 1.73" of rain. The last decade has been 3.2°F cooler on this date compared to 20-30 years ago.
The last decade has been 3.2°F cooler on this date compared to 20-30 years ago.
Planning for September 18th in Yellowstone? Great weather for outdoor activities.
Year by Year History
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 66°F | 27°F | 0" | 0" |
| 2024 | 48°F | 41°F | 1.73" | 0" |
| 2023 | 72°F | 28°F | 0" | 0" |
| 2022 | 60°F | 35°F | 0.28" | 0" |
| 2021 | 74°F | 28°F | 0" | 0" |
| 2020 | 77°F | 31°F | 0" | 0" |
| 2019 | 51°F | 24°F | 0.2" | 0" |
| 2018 | 74°F | 29°F | 0" | 0" |
| 2017 | 61°F | 29°F | 0" | 0" |
| 2016 | 67°F | 47°F | 0" | 0" |
| 2015 | 48°F | 36°F | 1.04" | 0" |
| 2014 | 78°F | 39°F | 0" | 0" |
| 2013 | 65°F | 43°F | 1.02" | 0" |
| 2012 | 73°F | 30°F | 0" | 0" |
| 2011 | 64°F | 32°F | 0" | 0" |
| 2010 | 76°F | 31°F | 0" | 0" |
| 2009 | 79°F | 34°F | 0" | 0" |
| 2008 | 79°F | 30°F | 0" | 0" |
| 2007 | 67°F | 42°F | 0" | 0" |
| 2006 | 64°F | 28°F | -- | -- |
| 2005 | 60°F | 24°F | -- | -- |
| 2004 | 78°F | 60°F | -- | -- |
| 2003 | 55°F | 22°F | -- | -- |
| 2002 | 57°F | 41°F | 0.38" | -- |
| 2001 | 69°F | 31°F | 0" | -- |
| 2000 | 73°F | 34°F | 0" | -- |
| 1999 | 78°F | 31°F | -- | -- |
| 1998 | 81°F | 39°F | -- | -- |
| 1997 | 73°F | 48°F | 0" | 0" |
| 1996 | 51°F | 30°F | 0.03" | 0" |
| 1995 | 71°F | 34°F | 0" | 0" |
| 1994 | 78°F | 28°F | 0" | 0" |
| 1993 | 63°F | 36°F | 0.1" | 0" |
| 1992 | 74°F | 25°F | 0" | 0" |
| 1991 | 66°F | 25°F | 0" | 0" |
| 1990 | 77°F | 30°F | 0" | 0" |
| 1989 | 71°F | 22°F | 0.64" | 0" |
| 1988 | 71°F | 30°F | 0" | 0" |
| 1987 | 70°F | 18°F | 0" | 0" |
| 1986 | 62°F | 34°F | 0.94" | -- |
| 1985 | 60°F | 39°F | 0.41" | 0" |
| 1984 | 80°F | 29°F | 0" | 0" |
| 1983 | 70°F | 28°F | 0" | 0" |
| 1982 | 69°F | 29°F | 0" | 0" |
| 1981 | 85°F | 27°F | 0" | 0" |
| 1980 | 69°F | 41°F | 0" | 0" |
| 1979 | 82°F | 24°F | 0" | 0" |
| 1978 | 56°F | 29°F | 1.14" | 0" |
| 1977 | 62°F | 22°F | 0.03" | 0" |
| 1976 | 74°F | 40°F | 0.58" | 0" |
| 1975 | 62°F | 24°F | 0" | 0" |
| 1974 | 82°F | 25°F | 0" | 0" |
| 1973 | 72°F | 27°F | 0" | 0" |
| 1972 | 74°F | 29°F | 0" | 0" |
| 1971 | 54°F | 14°F | 0" | 0" |