Weather on September 18 at Yosemite
Yosemite National Park
Based on 42 years of data from Mariposa, CA
Elevation Note: Yosemite sits at 4,000 ft. Expect temperatures 14°F cooler than the data shown below, which comes from Mariposa, CA at a lower elevation.
Planning Your Visit
September 18th in Yosemite National Park (via Mariposa, CA) typically brings warm fall weather, with average highs around 85°F and lows near 55°F — a 30°F daily swing. Over 42 years of records, the warmest September 18th was in 1991 (80°F average), while the coldest was 1993 (59°F) — a 21°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 1.7°F cooler on this date compared to 20-30 years ago.
The last decade has been 1.7°F cooler on this date compared to 20-30 years ago.
Planning for September 18th in Yosemite? Stay hydrated and seek shade during peak afternoon hours.
Year by Year History
| Year | High | Low | Precip | Snow |
|---|---|---|---|---|
| 2025 | 79°F | 59°F | -- | -- |
| 2024 | 74°F | 53°F | -- | -- |
| 2023 | 80°F | 56°F | -- | -- |
| 2022 | 68°F | 54°F | -- | -- |
| 2021 | 80°F | 55°F | -- | -- |
| 2020 | 81°F | 58°F | -- | -- |
| 2019 | 78°F | 49°F | -- | -- |
| 2018 | 82°F | 52°F | -- | -- |
| 2017 | 81°F | 53°F | -- | -- |
| 2016 | 95°F | 62°F | -- | -- |
| 2015 | 85°F | 51°F | -- | -- |
| 2014 | 82°F | 58°F | -- | -- |
| 2013 | 80°F | 50°F | -- | -- |
| 2012 | 88°F | 60°F | -- | -- |
| 2011 | 89°F | 55°F | -- | -- |
| 2010 | 84°F | 55°F | -- | -- |
| 2009 | 98°F | 62°F | -- | -- |
| 2008 | 83°F | 58°F | -- | -- |
| 2007 | 84°F | 53°F | -- | -- |
| 2006 | 89°F | 52°F | -- | -- |
| 2005 | 81°F | 47°F | -- | -- |
| 2004 | 70°F | 53°F | -- | -- |
| 2003 | 91°F | 52°F | -- | -- |
| 2002 | 89°F | 52°F | -- | -- |
| 2001 | 91°F | 58°F | -- | -- |
| 2000 | 99°F | 61°F | -- | -- |
| 1999 | 91°F | 63°F | -- | -- |
| 1998 | 79°F | 50°F | -- | -- |
| 1997 | 78°F | 54°F | -- | -- |
| 1996 | 80°F | 48°F | -- | -- |
| 1995 | 92°F | 56°F | -- | -- |
| 1994 | 88°F | 67°F | -- | -- |
| 1993 | 76°F | 43°F | -- | -- |
| 1992 | 85°F | 58°F | -- | -- |
| 1991 | 96°F | 65°F | -- | -- |
| 1990 | 76°F | 49°F | -- | -- |
| 1976 | 76°F | 50°F | 0" | 0" |
| 1975 | 92°F | 64°F | 0" | 0" |
| 1974 | 93°F | 60°F | 0" | 0" |
| 1973 | 85°F | 50°F | 0" | 0" |
| 1972 | 88°F | 51°F | 0" | 0" |
| 1971 | 93°F | 56°F | 0" | 0" |