Weather on June 21
Rancho Cucamonga, CA
55 Years of Data
Avg High
88°F
Avg Low
59°F
Warmest
2008
89°F avg
Coldest
2003
61°F avg
About This Date
June 21st in Rancho Cucamonga, CA typically brings warm summer weather, with average highs around 88°F and lows near 59°F — a 29°F daily swing. Over 42 years of records, the warmest June 21st was in 2008 (89°F average), while the coldest was 2003 (61°F) — a 28°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 5.9°F warmer on this date compared to 20-30 years ago.
The last decade has been 5.9°F warmer on this date compared to 20-30 years ago.
Planning for June 21st in Rancho Cucamonga, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
0.9°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 77° | 60° | 69° | — | — |
| 2024 | 93° | 61° | 77° | — | — |
| 2023 | 84° | 58° | 71° | — | — |
| 2022 | 96° | 65° | 80° | — | — |
| 2021 | 94° | 62° | 78° | — | — |
| 2020 | 86° | 63° | 74° | — | — |
| 2019 | 75° | 63° | 69° | — | — |
| 2018 | 91° | 60° | 76° | — | — |
| 2017 | 101° | 71° | 86° | — | — |
| 2016 | 96° | 71° | 84° | — | — |
| 2015 | 91° | 63° | 77° | — | — |
| 2014 | 93° | 63° | 78° | — | — |
| 2013 | 87° | 61° | 74° | — | — |
| 2012 | 85° | 59° | 72° | — | — |
| 2011 | 93° | 59° | 76° | — | — |
| 2010 | 79° | 57° | 68° | — | — |
| 2009 | 79° | 59° | 69° | — | — |
| 2008warmest | 106° | 73° | 89° | — | — |
| 2007 | 94° | 62° | 78° | — | — |
| 2006 | 92° | 59° | 75° | — | — |
| 2005 | 94° | 60° | 77° | — | — |
| 2004 | 77° | 55° | 66° | — | — |
| 2003coldest | 66° | 56° | 61° | — | — |
| 2002 | 76° | 60° | 68° | — | — |
| 2001 | 97° | 64° | 80° | — | — |
| 2000 | 90° | 60° | 75° | — | — |
| 1999 | 80° | 55° | 68° | — | — |
| 1998 | 85° | 54° | 69° | — | — |
| 1984 | 89° | 54° | 71° | — | — |
| 1983 | 82° | 56° | 69° | — | — |
| 1982 | 74° | 59° | 66° | — | — |
| 1981 | 95° | 61° | 78° | — | — |
| 1980 | 89° | 50° | 70° | — | — |
| 1979 | 84° | 49° | 66° | — | — |
| 1978 | 96° | 62° | 79° | — | — |
| 1977 | 82° | 50° | 66° | — | — |
| 1976 | 87° | 54° | 70° | — | — |
| 1975 | 82° | 46° | 64° | — | — |
| 1974 | 90° | 54° | 72° | — | — |
| 1973 | 107° | 63° | 85° | — | — |
| 1972 | 85° | 60° | 72° | — | — |
| 1971 | 94° | 60° | 77° | — | — |
42 years of data from ONTARIO INTL AP