Climate averages 1991–2020
Folsom 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 Folsom: daytime highs average 30.7°C and nights cool to about 15.3°C. By daytime temperature it is the 4th warmest of the 12 months.
Expect about 4.2 mm of rain on fewer than one day, which makes September a very dry month (the 3rd driest of the 12 months). Daylight, from sunrise to sunset, lasts about 12 h 29 min on an average September day.
The nearest other city in this atlas is Citrus Heights (10 km away). In September its highs average 30.8°C, about as warm as Folsom, with 4.2 mm of rain.
Among the 498 cities listed in the United States, Folsom ranks joint 75th of 498 for the warmest September highs and joint 70th of 498 for the driest September (rainfall, lowest first). The mean September high of those 498 cities is 26.9°C; Folsom is 3.8°C warmer than that mean.
From September to October, average highs fall by 5.8°C to 24.9°C, and monthly rainfall rises from 4.2 mm to 41 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
Folsom climate table
| Month | Average highHigh / low | Average low | Rainfall mm/month | Rain days ≥1 mm/day | Daylight hours/dayDaylight h/day |
|---|---|---|---|---|---|
| January | 13.4°C3.8°C | 3.8°C | 142 | 10.1 | 9.810 h |
| February | 15.2°C4.8°C | 4.8°C | 136 | 9.8 | 10.711 h |
| March | 17.6°C6.5°C | 6.5°C | 120 | 9.6 | 11.912 h |
| April | 20.8°C8.4°C | 8.4°C | 57 | 6.4 | 13.213 h |
| May | 25.8°C11.7°C | 11.7°C | 33 | 4.5 | 14.314 h |
| June | 30.9°C15.0°C | 15.0°C | 6.8 | 1.2 | 14.815 h |
| July | 33.7°C17.1°C | 17.1°C | 0.3 | 0.1 | 14.615 h |
| August | 33.1°C16.9°C | 16.9°C | 1.1 | 0.1 | 13.714 h |
| September, selected | 30.7°C15.3°C | 15.3°C | 4.2 | 0.8 | 12.512 h |
| October | 24.9°C11.5°C | 11.5°C | 41 | 3.3 | 11.211 h |
| November | 17.5°C6.7°C | 6.7°C | 77 | 6.9 | 10.110 h |
| December | 13.1°C3.8°C | 3.8°C | 143 | 10.4 | 9.510 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
- Citrus Heights in SeptemberUnited States · 10 kmHigh 30.8°C · Low 15.3°C · 4.2 mm rain
- Roseville in SeptemberUnited States · 13 kmHigh 30.9°C · Low 15.4°C · 4.2 mm rain
- Rancho Cordova in SeptemberUnited States · 15 kmHigh 30.8°C · Low 15.3°C · 3.5 mm rain
- Arden-Arcade in SeptemberUnited States · 19 kmHigh 30.9°C · Low 15.4°C · 2.3 mm rain
- Sacramento in SeptemberUnited States · 30 kmHigh 31.1°C · Low 15.4°C · 2.3 mm rain
- Elk Grove in SeptemberUnited States · 34 kmHigh 30.3°C · Low 15.0°C · 3.5 mm rain
- Vacaville in SeptemberUnited States · 79 kmHigh 30.4°C · Low 15.3°C · 1.5 mm rain
- Stockton in SeptemberUnited States · 81 kmHigh 30.1°C · Low 15.1°C · 2.1 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 Folsom) is explained once on the Folsom year overview and on the Sources, method and limits page.
Roseville and Citrus Heights lie in the same rainfall cell, so their rainfall figures are identical to these; temperatures differ because they come from smaller 0.1° cells.