Climate averages 1991–2020
Chico weather
in September.
A hot, very dry month: the 4th warmest and the 3rd driest of the year.
Long-term climate patterns, not a forecast for a particular trip.
September is a hot month in Chico: daytime highs average 31.9°C and nights cool to about 16.3°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 7.5 mm of rain on roughly 1 day, which makes September a very dry month (the 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 30 min on an average September day.
The nearest other city in this atlas is Redding (106 km away). In September its highs average 32.1°C, about as warm as Chico, with 13 mm of rain.
Among the 498 cities listed in the United States, Chico ranks joint 30th of 498 for the warmest September highs and 101st of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Chico is 5.0°C warmer than that mean.
From September to October, average highs fall by 6.5°C to 25.4°C, and monthly rainfall rises from 7.5 mm to 52 mm.
The annual picture
September in context
Monthly rainfall
Average total · mmAverages from hourly ERA5 reanalysis data. Actual weather varies from year to year. How these numbers are calculated
Every month, side by side
Chico climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 13.7°C3.9°C | 3.9°C | 184 | 11.1 | 9.710 h |
| February | 15.1°C4.6°C | 4.6°C | 178 | 10.4 | 10.711 h |
| March | 17.6°C6.2°C | 6.2°C | 149 | 10.8 | 11.912 h |
| April | 21.1°C8.5°C | 8.5°C | 73 | 7.4 | 13.213 h |
| May | 26.7°C12.8°C | 12.8°C | 47 | 5.1 | 14.314 h |
| June | 32.3°C17.0°C | 17.0°C | 14 | 1.7 | 14.915 h |
| July | 36.1°C19.9°C | 19.9°C | 0.5 | 0.1 | 14.715 h |
| August | 34.9°C19.0°C | 19.0°C | 1.6 | 0.3 | 13.714 h |
| September, selected | 31.9°C16.3°C | 16.3°C | 7.5 | 1.2 | 12.512 h |
| October | 25.4°C11.9°C | 11.9°C | 52 | 3.8 | 11.211 h |
| November | 17.6°C6.8°C | 6.8°C | 105 | 8.0 | 10.010 h |
| December | 13.2°C3.9°C | 3.9°C | 202 | 11.5 | 9.49 h |
Rainfall is the average of the 30 separate monthly totals. A rain day is a local calendar day with at least 1 mm of precipitation. Daylight is the calculated sunrise-to-sunset length, not measured sunshine.
Compare places
September in nearby cities
- Redding in SeptemberUnited States · 106 kmHigh 32.1°C · Low 16.7°C · 13 mm rain
- Roseville in SeptemberUnited States · 118 kmHigh 30.9°C · Low 15.4°C · 4.2 mm rain
- Citrus Heights in SeptemberUnited States · 123 kmHigh 30.8°C · Low 15.3°C · 4.2 mm rain
- Folsom in SeptemberUnited States · 130 kmHigh 30.7°C · Low 15.3°C · 4.2 mm rain
- Sacramento in SeptemberUnited States · 131 kmHigh 31.1°C · Low 15.4°C · 2.3 mm rain
- Arden-Arcade in SeptemberUnited States · 131 kmHigh 30.9°C · Low 15.4°C · 2.3 mm rain
- Rancho Cordova in SeptemberUnited States · 135 kmHigh 30.8°C · Low 15.3°C · 3.5 mm rain
- Elk Grove in SeptemberUnited States · 152 kmHigh 30.3°C · Low 15.0°C · 3.5 mm rain
Read the numbers correctly
Climate, not a promise.
These patterns help compare months. They cannot tell you the weather on a specific day of your trip.
Sources, method and limitsHow these numbers are made (what the highs, lows and rain days mean, the sources and the model cell used for Chico) is explained once on the Chico year overview and on the Sources, method and limits page.