Weather on September 21
El Monte, CA
55 Years of Data
Avg High
87°F
Avg Low
60°F
Warmest
2021
82°F avg
Coldest
1988
63°F avg
About This Date
September 21st in El Monte, CA typically brings warm fall weather, with average highs around 87°F and lows near 60°F — a 27°F daily swing. Over 55 years of records, the warmest September 21st was in 2021 (82°F average), while the coldest was 1988 (63°F) — a 19°F range across recorded history. Rain or other precipitation has occurred on about 7% of September 21st dates historically. The last decade has been 1.1°F cooler on this date compared to 20-30 years ago.
The last decade has been 1.1°F cooler on this date compared to 20-30 years ago.
Planning for September 21st in El Monte, CA? Stay hydrated and seek shade during peak afternoon hours.
Cooling Trend
0.4°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 85° | 61° | 73° | — | — |
| 2024 | 78° | 58° | 68° | — | — |
| 2023 | 73° | 58° | 65° | — | — |
| 2022 | 82° | 61° | 71° | — | — |
| 2021warmest | 102° | 62° | 82° | — | — |
| 2020 | 86° | 60° | 73° | — | — |
| 2019 | 92° | 62° | 77° | — | — |
| 2018 | 83° | 60° | 71° | — | — |
| 2017 | 72° | 56° | 64° | — | — |
| 2016 | 89° | 66° | 78° | — | — |
| 2015 | 89° | 67° | 78° | — | — |
| 2014 | 82° | 64° | 73° | — | — |
| 2013 | 77° | 64° | 71° | — | — |
| 2012 | 94° | 65° | 79° | — | — |
| 2011 | 90° | 58° | 74° | — | — |
| 2010 | 77° | 60° | 69° | — | — |
| 2009 | 95° | 62° | 79° | — | — |
| 2008 | 78° | 60° | 69° | — | — |
| 2007 | 76° | 54° | 65° | 0.08" | — |
| 2006 | 80° | 57° | 69° | — | — |
| 2005 | 85° | 57° | 71° | 0.03" | — |
| 2004 | 88° | 53° | 70° | — | — |
| 2003 | 100° | 60° | 80° | — | — |
| 2002 | 93° | 58° | 75° | — | — |
| 2001 | 89° | 55° | 72° | — | — |
| 2000 | 77° | 65° | 71° | — | — |
| 1999 | 89° | 59° | 74° | — | — |
| 1998 | 74° | 64° | 69° | — | — |
| 1997 | 92° | 58° | 75° | — | — |
| 1996 | 89° | 62° | 76° | — | — |
| 1995 | 88° | 57° | 72° | — | — |
| 1994 | 86° | 56° | 71° | — | — |
| 1993 | 79° | 64° | 71° | — | — |
| 1992 | 97° | 60° | 78° | — | — |
| 1991 | 90° | 64° | 77° | — | — |
| 1990 | 83° | 65° | 74° | — | — |
| 1989 | 98° | 58° | 78° | — | — |
| 1988coldest | 72° | 55° | 63° | 0.13" | — |
| 1987 | 96° | 60° | 78° | — | — |
| 1986 | 80° | 50° | 65° | — | — |
| 1985 | 93° | 56° | 74° | — | — |
| 1984 | 91° | 66° | 79° | — | — |
| 1983 | 90° | 72° | 81° | 0.38" | — |
| 1982 | 93° | 56° | 74° | — | — |
| 1981 | 91° | 61° | 76° | — | — |
| 1980 | 80° | 62° | 71° | — | — |
| 1979 | 93° | 64° | 79° | — | — |
| 1978 | 94° | 52° | 73° | — | — |
| 1977 | 86° | 54° | 70° | — | — |
| 1976 | 80° | 65° | 72° | — | — |
| 1975 | 91° | 58° | 74° | — | — |
| 1974 | 97° | 63° | 80° | — | — |
| 1973 | 82° | 53° | 68° | — | — |
| 1972 | 99° | 55° | 77° | — | — |
| 1971 | 78° | 62° | 70° | — | — |
55 years of data from SAN GABRIEL FIRE DEPT