Weather on May 20
Rancho Cucamonga, CA
55 Years of Data
Avg High
79°F
Avg Low
54°F
Warmest
2000
79°F avg
Coldest
1975
52°F avg
About This Date
May 20th 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 20th was in 2000 (79°F average), while the coldest was 1975 (52°F) — a 27°F range across recorded history. Rain or other precipitation has occurred on about 7% of May 20th dates historically, with the wettest May 20th recording 0.91" of rain. The last decade has been 2.6°F cooler on this date compared to 20-30 years ago.
The last decade has been 2.6°F cooler on this date compared to 20-30 years ago.
Planning for May 20th in Rancho Cucamonga, CA? Great weather for outdoor activities.
Warming Trend
1.6°F per decade on this date
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 94° | 59° | 76° | — | — |
| 2024 | 71° | 55° | 63° | — | — |
| 2023 | 85° | 60° | 72° | — | — |
| 2022 | 65° | 55° | 60° | — | — |
| 2021 | 73° | 58° | 65° | — | — |
| 2020 | 80° | 54° | 67° | — | — |
| 2019 | 71° | 53° | 62° | — | — |
| 2018 | 71° | 58° | 64° | — | — |
| 2017 | 96° | 59° | 78° | — | — |
| 2016 | 72° | 56° | 64° | — | — |
| 2015 | 76° | 56° | 66° | — | — |
| 2014 | 72° | 55° | 63° | — | — |
| 2013 | 95° | 58° | 76° | — | — |
| 2012 | 97° | 57° | 77° | — | — |
| 2011 | 74° | 51° | 62° | — | — |
| 2010 | 83° | 54° | 68° | — | — |
| 2009 | 89° | 59° | 74° | — | — |
| 2008 | 81° | 61° | 71° | — | — |
| 2007 | 76° | 54° | 65° | — | — |
| 2006 | 85° | 61° | 73° | — | — |
| 2005 | 91° | 63° | 77° | — | — |
| 2004 | 74° | 55° | 64° | — | — |
| 2003 | 97° | 60° | 78° | — | — |
| 2002 | 64° | 51° | 58° | 0.51" | — |
| 2001 | 80° | 57° | 69° | — | — |
| 2000warmest | 98° | 60° | 79° | — | — |
| 1999 | 72° | 55° | 63° | — | — |
| 1984 | 86° | 51° | 69° | — | — |
| 1983 | 90° | 48° | 69° | — | — |
| 1982 | 79° | 50° | 64° | — | — |
| 1981 | 67° | 49° | 58° | — | — |
| 1980 | 79° | 55° | 67° | — | — |
| 1979 | 70° | 53° | 61° | — | — |
| 1978 | 83° | 52° | 67° | — | — |
| 1977 | 83° | 45° | 64° | — | — |
| 1976 | 78° | 52° | 65° | — | — |
| 1975coldest | 58° | 46° | 52° | 0.91" | — |
| 1974 | 77° | 38° | 57° | — | — |
| 1973 | 70° | 54° | 62° | — | — |
| 1972 | 64° | 42° | 53° | 0.1" | — |
| 1971 | 79° | 47° | 63° | — | — |
41 years of data from ONTARIO INTL AP