Weather on August 15
Rancho Cucamonga, CA
55 Years of Data
Avg High
93°F
Avg Low
64°F
Warmest
2020
94°F avg
Coldest
1976
63°F avg
About This Date
August 15th in Rancho Cucamonga, CA typically brings hot summer weather, with average highs around 93°F and lows near 64°F — a 29°F daily swing. Over 41 years of records, the warmest August 15th was in 2020 (94°F average), while the coldest was 1976 (63°F) — a 31°F range across recorded history. Rain or other precipitation has occurred on about 2% of August 15th dates historically, with the wettest August 15th recording 0.76" of rain. The last decade has been 4.3°F warmer on this date compared to 20-30 years ago.
The last decade has been 4.3°F warmer on this date compared to 20-30 years ago.
Planning for August 15th in Rancho Cucamonga, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
2.3°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 87° | 63° | 75° | — | — |
| 2024 | 96° | 68° | 82° | — | — |
| 2023 | 101° | 67° | 84° | — | — |
| 2022 | 98° | 69° | 84° | — | — |
| 2021 | 100° | 71° | 86° | — | — |
| 2020warmest | 110° | 78° | 94° | — | — |
| 2019 | 99° | 66° | 82° | — | — |
| 2018 | 93° | 67° | 80° | — | — |
| 2017 | 80° | 62° | 71° | — | — |
| 2016 | 106° | 72° | 89° | — | — |
| 2015 | 108° | 71° | 89° | — | — |
| 2014 | 98° | 67° | 82° | — | — |
| 2013 | 99° | 64° | 81° | — | — |
| 2012 | 96° | 70° | 83° | — | — |
| 2011 | 92° | 62° | 77° | — | — |
| 2010 | 94° | 58° | 76° | — | — |
| 2009 | 88° | 62° | 75° | — | — |
| 2008 | 93° | 68° | 81° | — | — |
| 2007 | 100° | 72° | 86° | — | — |
| 2006 | 87° | 60° | 74° | — | — |
| 2005 | 79° | 61° | 70° | 0.76" | — |
| 2004 | 90° | 64° | 77° | — | — |
| 2003 | 100° | 71° | 86° | — | — |
| 2002 | 89° | 61° | 75° | — | — |
| 2001 | 100° | 64° | 82° | — | — |
| 2000 | 99° | 70° | 84° | — | — |
| 1999 | 90° | 58° | 74° | — | — |
| 1998 | 92° | 66° | 79° | — | — |
| 1983 | 97° | 70° | 83° | — | — |
| 1982 | 88° | 53° | 70° | — | — |
| 1981 | 95° | 69° | 82° | — | — |
| 1980 | 81° | 66° | 73° | — | — |
| 1979 | 87° | 53° | 70° | — | — |
| 1978 | 90° | 55° | 72° | — | — |
| 1977 | 103° | 61° | 82° | — | — |
| 1976coldest | 70° | 57° | 63° | — | — |
| 1975 | 83° | 49° | 66° | — | — |
| 1974 | 85° | 50° | 67° | — | — |
| 1973 | 92° | 62° | 77° | — | — |
| 1972 | 79° | 55° | 67° | — | — |
| 1971 | 91° | 59° | 75° | — | — |
41 years of data from ONTARIO INTL AP