Weather on September 20 at Mount Rainier
Mount Rainier National Park
Based on 54 years of data from Seattle, WA
Elevation Note: Mount Rainier sits at 5,400 ft. Expect temperatures 19°F cooler than the data shown below, which comes from Seattle, WA at a lower elevation.
Planning Your Visit
September 20th in Mount Rainier National Park (via Seattle, WA) typically brings mild fall weather, with average highs around 68°F and lows near 53°F. Over 54 years of records, the warmest September 20th was in 1974 (70°F average), while the coldest was 1993 (53°F) — a 17°F range across recorded history. Rain or other precipitation has occurred on about 33% of September 20th dates historically, with the wettest September 20th recording 1.02" of rain. The last decade has been 1.5°F warmer on this date compared to 20-30 years ago.
The last decade has been 1.5°F warmer on this date compared to 20-30 years ago.
Planning for September 20th in Mount Rainier? Great weather for outdoor activities. Consider bringing rain gear or an umbrella.
Year by Year History
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 75°F | 53°F | 0" | -- |
| 2024 | 67°F | 54°F | 0.1" | -- |
| 2023 | 64°F | 50°F | 0.33" | -- |
| 2022 | 78°F | 55°F | 0" | -- |
| 2021 | 69°F | 54°F | 0" | -- |
| 2020 | 72°F | 57°F | 0" | -- |
| 2019 | 68°F | 58°F | 0" | -- |
| 2018 | 66°F | 55°F | 0.46" | -- |
| 2017 | 60°F | 51°F | 0.1" | -- |
| 2016 | 67°F | 49°F | 0" | -- |
| 2015 | 76°F | 57°F | 0.23" | -- |
| 2014 | 74°F | 60°F | 0" | -- |
| 2013 | 75°F | 55°F | 0.38" | -- |
| 2012 | 70°F | 52°F | 0" | -- |
| 2011 | 77°F | 49°F | 0" | -- |
| 2010 | 67°F | 57°F | 0" | -- |
| 2009 | 68°F | 52°F | 0" | -- |
| 2008 | 59°F | 54°F | 1.02" | -- |
| 2007 | 61°F | 48°F | 0" | -- |
| 2006 | 56°F | 53°F | 0.89" | -- |
| 2005 | 67°F | 55°F | 0" | -- |
| 2004 | 65°F | 47°F | 0" | -- |
| 2003 | 67°F | 50°F | 0" | -- |
| 2002 | 67°F | 48°F | 0" | -- |
| 2001 | 67°F | 52°F | 0" | -- |
| 2000 | 66°F | 55°F | 0.08" | -- |
| 1999 | 78°F | 58°F | 0" | -- |
| 1997 | 74°F | 48°F | 0" | 0" |
| 1996 | 59°F | 50°F | 0.25" | 0" |
| 1995 | 78°F | 54°F | 0" | 0" |
| 1994 | 77°F | 56°F | 0" | 0" |
| 1993 | 60°F | 47°F | 0" | 0" |
| 1992 | 66°F | 58°F | 0.03" | 0" |
| 1991 | 63°F | 49°F | 0" | 0" |
| 1990 | 71°F | 53°F | 0" | 0" |
| 1989 | 69°F | 48°F | 0" | 0" |
| 1988 | 65°F | 50°F | 0" | 0" |
| 1987 | 79°F | 54°F | 0" | 0" |
| 1986 | 63°F | 50°F | 0" | 0" |
| 1985 | 64°F | 48°F | 0" | 0" |
| 1984 | 65°F | 55°F | 0.23" | 0" |
| 1983 | 67°F | 44°F | 0" | 0" |
| 1982 | 67°F | 56°F | 0.1" | 0" |
| 1981 | 65°F | 53°F | 0.23" | 0" |
| 1980 | 66°F | 54°F | 0" | 0" |
| 1979 | 66°F | 62°F | 0" | 0" |
| 1978 | 60°F | 54°F | 0.69" | 0" |
| 1977 | 63°F | 49°F | 0.69" | 0" |
| 1976 | 82°F | 56°F | 0" | 0" |
| 1975 | 79°F | 49°F | 0" | 0" |
| 1974 | 85°F | 55°F | 0" | 0" |
| 1973 | 64°F | 54°F | 0.71" | 0" |
| 1972 | 60°F | 50°F | 0.25" | 0" |
| 1971 | 71°F | 55°F | 0" | 0" |