Weather on September 20
Rancho Cucamonga, CA
55 Years of Data
About This Date
September 20th in Rancho Cucamonga, CA typically brings warm fall weather, with average highs around 86°F and lows near 60°F — a 26°F daily swing. Over 41 years of records, the warmest September 20th was in 2015 (87°F average), while the coldest was 1973 (63°F) — a 24°F range across recorded history. Rain or other precipitation has occurred on about 7% of September 20th dates historically, with the wettest September 20th recording 0.74" of rain. The last decade has been 2.6°F warmer on this date compared to 20-30 years ago.
The last decade has been 2.6°F warmer on this date compared to 20-30 years ago.
Planning for September 20th in Rancho Cucamonga, CA? Stay hydrated and seek shade during peak afternoon hours.
| Year | High | Low | Avg | Precip | Snow |
|---|---|---|---|---|---|
| 2025 | 92° | 67° | 79° | — | — |
| 2024 | 78° | 60° | 69° | — | — |
| 2023 | 78° | 62° | 70° | 0.05" | — |
| 2022 | 86° | 60° | 73° | — | — |
| 2021 | 93° | 62° | 78° | — | — |
| 2020 | 94° | 64° | 79° | — | — |
| 2019 | 86° | 63° | 74° | — | — |
| 2018 | 90° | 62° | 76° | — | — |
| 2017 | 79° | 64° | 71° | — | — |
| 2016 | 84° | 70° | 77° | — | — |
| 2015warmest | 104° | 70° | 87° | — | — |
| 2014 | 82° | 64° | 73° | — | — |
| 2013 | 78° | 63° | 70° | — | — |
| 2012 | 101° | 65° | 83° | — | — |
| 2011 | 89° | 60° | 75° | — | — |
| 2010 | 88° | 58° | 73° | — | — |
| 2009 | 92° | 62° | 77° | — | — |
| 2008 | 84° | 60° | 72° | — | — |
| 2007 | 70° | 56° | 63° | 0.13" | — |
| 2006 | 84° | 58° | 71° | — | — |
| 2005 | 78° | 63° | 70° | 0.74" | — |
| 2004 | 77° | 55° | 66° | — | — |
| 2003 | 96° | 61° | 78° | — | — |
| 2002 | 94° | 59° | 76° | — | — |
| 2001 | 85° | 57° | 71° | — | — |
| 2000 | 85° | 63° | 74° | — | — |
| 1999 | 92° | 53° | 72° | — | — |
| 1998 | 75° | 62° | 69° | — | — |
| 1983 | 88° | 68° | 78° | — | — |
| 1982 | 90° | 51° | 70° | — | — |
| 1981 | 94° | 62° | 78° | — | — |
| 1980 | 81° | 52° | 66° | — | — |
| 1979 | 95° | 66° | 81° | — | — |
| 1978 | 86° | 50° | 68° | — | — |
| 1977 | 77° | 50° | 64° | — | — |
| 1976 | 75° | 60° | 68° | — | — |
| 1975 | 88° | 59° | 73° | — | — |
| 1974 | 90° | 55° | 72° | — | — |
| 1973coldest | 77° | 48° | 63° | — | — |
| 1972 | 91° | 50° | 71° | — | — |
| 1971 | 83° | 53° | 68° | — | — |
Rancho Cucamonga, CA Temperature Range by Month
Average monthly highs and lows. The shaded band shows the typical daily temperature range.
Rancho Cucamonga, CA Monthly Precipitation
Average rainfall per month, in inches.
Rancho Cucamonga, CA Daily Temperature Calendar
Average daily high temperature for every day of the year. Each cell is the climatological mean for that calendar day across 55 years of NOAA data.
Best Time to Visit Rancho Cucamonga, CA
Rancho Cucamonga, CA has no months that meet our "pleasant" threshold — every season has tradeoffs.