Weather on May 18
Rancho Cucamonga, CA
55 Years of Data
Avg High
79°F
Avg Low
54°F
Warmest
2008
85°F avg
Coldest
1974
53°F avg
About This Date
May 18th in Rancho Cucamonga, CA typically brings pleasant spring weather, with average highs around 79°F and lows near 54°F — a 25°F daily swing. Over 41 years of records, the warmest May 18th was in 2008 (85°F average), while the coldest was 1974 (53°F) — a 32°F range across recorded history. Rain or other precipitation has occurred on about 7% of May 18th dates historically, with the wettest May 18th recording 0.53" of rain. The last decade has been 1.6°F cooler on this date compared to 20-30 years ago.
The last decade has been 1.6°F cooler on this date compared to 20-30 years ago.
Planning for May 18th in Rancho Cucamonga, CA? Great weather for outdoor activities.
Warming Trend
0.7°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 74° | 55° | 64° | — | — |
| 2024 | 76° | 54° | 65° | — | — |
| 2023 | 78° | 56° | 67° | — | — |
| 2022 | 83° | 56° | 69° | — | — |
| 2021 | 80° | 58° | 69° | — | — |
| 2020 | 69° | 58° | 63° | 0.33" | — |
| 2019 | 77° | 54° | 65° | — | — |
| 2018 | 74° | 57° | 65° | — | — |
| 2017 | 82° | 49° | 65° | — | — |
| 2016 | 82° | 59° | 71° | — | — |
| 2015 | 70° | 55° | 62° | — | — |
| 2014 | 82° | 59° | 71° | — | — |
| 2013 | 79° | 60° | 69° | — | — |
| 2012 | 76° | 58° | 67° | — | — |
| 2011 | 61° | 49° | 55° | 0.53" | — |
| 2010 | 69° | 53° | 61° | 0.03" | — |
| 2009 | 93° | 61° | 77° | — | — |
| 2008warmest | 101° | 69° | 85° | — | — |
| 2007 | 80° | 56° | 68° | — | — |
| 2006 | 82° | 61° | 71° | — | — |
| 2005 | 80° | 55° | 68° | — | — |
| 2004 | 77° | 60° | 69° | — | — |
| 2003 | 77° | 55° | 66° | — | — |
| 2002 | 75° | 55° | 65° | — | — |
| 2001 | 77° | 59° | 68° | — | — |
| 2000 | 88° | 51° | 69° | — | — |
| 1999 | 84° | 55° | 70° | — | — |
| 1984 | 90° | 48° | 69° | — | — |
| 1983 | 88° | 48° | 68° | — | — |
| 1982 | 88° | 52° | 70° | — | — |
| 1981 | 81° | 46° | 63° | — | — |
| 1980 | 85° | 51° | 68° | — | — |
| 1979 | 74° | 49° | 61° | — | — |
| 1978 | 92° | 51° | 71° | — | — |
| 1977 | 72° | 41° | 56° | — | — |
| 1976 | 85° | 48° | 66° | — | — |
| 1975 | 75° | 47° | 61° | — | — |
| 1974coldest | 65° | 41° | 53° | — | — |
| 1973 | 83° | 52° | 67° | — | — |
| 1972 | 68° | 53° | 61° | — | — |
| 1971 | 84° | 49° | 66° | — | — |
41 years of data from ONTARIO INTL AP