Weather on May 31
Rancho Cucamonga, CA
55 Years of Data
Avg High
82°F
Avg Low
56°F
Warmest
2025
80°F avg
Coldest
1980
55°F avg
About This Date
May 31st in Rancho Cucamonga, CA typically brings warm spring weather, with average highs around 82°F and lows near 56°F — a 26°F daily swing. Over 42 years of records, the warmest May 31st was in 2025 (80°F average), while the coldest was 1980 (55°F) — a 25°F range across recorded history. This date has historically been dry, with little recorded precipitation. The last decade has been 2.0°F cooler on this date compared to 20-30 years ago.
The last decade has been 2.0°F cooler on this date compared to 20-30 years ago.
Planning for May 31st in Rancho Cucamonga, CA? Stay hydrated and seek shade during peak afternoon hours.
Warming Trend
1.4°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025warmest | 96° | 64° | 80° | — | — |
| 2024 | 80° | 57° | 69° | — | — |
| 2023 | 63° | 56° | 59° | — | — |
| 2022 | 82° | 55° | 69° | — | — |
| 2021 | 86° | 60° | 73° | — | — |
| 2020 | 87° | 59° | 73° | — | — |
| 2019 | 83° | 60° | 71° | — | — |
| 2018 | 76° | 57° | 66° | — | — |
| 2017 | 72° | 61° | 66° | — | — |
| 2016 | 80° | 55° | 68° | — | — |
| 2015 | 83° | 57° | 70° | — | — |
| 2014 | 90° | 60° | 75° | — | — |
| 2013 | 89° | 61° | 75° | — | — |
| 2012 | 94° | 57° | 75° | — | — |
| 2011 | 82° | 53° | 68° | — | — |
| 2010 | 82° | 56° | 69° | — | — |
| 2009 | 76° | 60° | 68° | — | — |
| 2008 | 79° | 54° | 66° | — | — |
| 2007 | 80° | 53° | 67° | — | — |
| 2006 | 96° | 62° | 79° | — | — |
| 2005 | 83° | 56° | 69° | — | — |
| 2004 | 94° | 60° | 77° | — | — |
| 2003 | 85° | 59° | 72° | — | — |
| 2002 | 89° | 58° | 73° | — | — |
| 2001 | 94° | 60° | 77° | — | — |
| 2000 | 85° | 58° | 71° | — | — |
| 1999 | 80° | 53° | 67° | — | — |
| 1998 | 79° | 52° | 65° | — | — |
| 1984 | 89° | 58° | 73° | — | — |
| 1983 | 65° | 56° | 60° | — | — |
| 1982 | 74° | 45° | 59° | — | — |
| 1981 | 85° | 60° | 72° | — | — |
| 1980coldest | 60° | 50° | 55° | — | — |
| 1979 | 76° | 50° | 63° | — | — |
| 1978 | 81° | 49° | 65° | — | — |
| 1977 | 91° | 55° | 73° | — | — |
| 1976 | 79° | 45° | 62° | — | — |
| 1975 | 83° | 51° | 67° | — | — |
| 1974 | 70° | 51° | 60° | — | — |
| 1973 | 73° | 55° | 64° | — | — |
| 1972 | 91° | 61° | 76° | — | — |
| 1971 | 65° | 48° | 56° | — | — |
42 years of data from ONTARIO INTL AP