Average temperature in September is 20 °C
Average daytime temperature is 27.6 °C
Average night temperature is 12.3 °C
Absolute maximum temperature: 34.1 °C
Absolute minimum temperature: 7.8 °C
Number of sunny days: 21
Number of rainy days: 9
Number of snow days:
Precipitation sum: 15 mm
* Weather data for Riverside United States is based on climate observations for 2023 year
| September (°C) | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Maximum temperature | 33.8 | 32.3 | 31.4 | 31.5 | 30.4 | 32.4 | 34.1 | 33.2 | 31.8 | 31 | 27.6 | 21.9 | 19.2 | 20.9 | 23 | 22.6 | 24.2 | 23.4 | 23.5 | 26.1 | 26.4 | 28.7 | 26.2 | 23.6 | 27.2 | 28.3 | 27.5 | 29.7 | 29.6 | 27.3 |
| Apparent max temperature | 31.4 | 30.7 | 30.5 | 27.2 | 26.9 | 26.8 | 31.4 | 30.9 | 30.3 | 27.8 | 25 | 20 | 18.2 | 20.4 | 21.2 | 21.6 | 23.1 | 22.1 | 22.5 | 22.3 | 22.5 | 23.9 | 21.6 | 21.3 | 24.2 | 26.3 | 25.4 | 27.4 | 24.8 | 23.1 |
| Mean temperature | 25.3 | 24.8 | 24 | 24.7 | 21.5 | 23.5 | 25.5 | 23.2 | 24.2 | 23.8 | 21.2 | 17.2 | 15.9 | 15.3 | 15.5 | 14.8 | 16.9 | 17.5 | 16.3 | 16.9 | 17.8 | 19.3 | 18.6 | 17.4 | 18.3 | 19.8 | 19.5 | 19.9 | 19.7 | 20.5 |
| Apparent mean temperature | 14.1 | 12.4 | 14.6 | 18.2 | 10.8 | 12.8 | 15.3 | 8.9 | 12.7 | 13.8 | 14.5 | 11.2 | 12.1 | 8.7 | 7.5 | 6.3 | 7.6 | 10.4 | 7.4 | 6.6 | 8 | 7.8 | 9.8 | 8.7 | 5.9 | 9.3 | 5.3 | 5.6 | 7.8 | 8.8 |
| Minimum temperature | 16.5 | 14.7 | 15.9 | 19.4 | 12.9 | 15.5 | 17.6 | 12.6 | 16.1 | 15.9 | 14.4 | 13.4 | 12.8 | 9.7 | 9 | 7.8 | 9.6 | 11.7 | 8.7 | 8.9 | 10.5 | 10.6 | 12.9 | 10.2 | 8.4 | 11.5 | 8.8 | 9.1 | 11.1 | 13.1 |
| Apparent min temperature | 22.9 | 22 | 22.4 | 22.3 | 18.8 | 20 | 22.7 | 19.5 | 21.1 | 21.2 | 19.6 | 15.6 | 15.4 | 14.7 | 14.6 | 13.2 | 15.5 | 16.2 | 15 | 14.1 | 14.8 | 16.3 | 15.2 | 15.8 | 16.1 | 17.6 | 16.6 | 16.7 | 16.5 | 16.6 |
| September | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 | 21 | 22 | 23 | 24 | 25 | 26 | 27 | 28 | 29 | 30 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Daylight duration (h) | 12.9 | 12.9 | 12.9 | 12.8 | 12.8 | 12.8 | 12.7 | 12.7 | 12.7 | 12.6 | 12.6 | 12.5 | 12.5 | 12.5 | 12.4 | 12.4 | 12.4 | 12.3 | 12.3 | 12.2 | 12.2 | 12.2 | 12.1 | 12.1 | 12.1 | 12 | 12 | 11.9 | 11.9 | 11.9 |
| Sunshine duration (h) | 12 | 12 | 12 | 11.9 | 11.9 | 11.9 | 11.9 | 11.9 | 11.8 | 11.4 | 10.6 | 8.3 | 9.5 | 11.7 | 9.8 | 11.6 | 11.5 | 11 | 10.7 | 10.5 | 9.7 | 11.4 | 9.7 | 10.9 | 11.2 | 11.2 | 11.2 | 11.1 | 11.1 | 11 |
| Precipitation (mm) | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0.1 | 5 | 2.1 | 4.3 | 0.5 | 1.5 | 0 | 0 | 0.6 | 0 | 0 | 0 | 0 | 0 | 0.9 | 0 | 0 | 0 | 0 | 0 | 0.4 |
| Precipitation hours | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 1 | 4 | 5 | 4 | 3 | 3 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 2 | 0 | 0 | 0 | 0 | 0 | 1 |
| Wind speed (m/s) | 24.7 | 27 | 15 | 20.2 | 25 | 32.9 | 17.6 | 17.4 | 19.1 | 25.6 | 26.6 | 21.3 | 14.6 | 17.2 | 18.7 | 12.7 | 12.1 | 22.2 | 15.6 | 28.7 | 24.9 | 23.5 | 19.7 | 16.8 | 16.6 | 14.8 | 10.2 | 16.6 | 30.4 | 33.1 |
In September 2023, the highest daytime temperature in Riverside was 34.1°C.
While the minimum temperature at night dropped to 7.8°C.
The average nighttime and daytime temperatures during September in Riverside are 12.3°C and 27.6°C respectively.
The precipitation sum in September is about 15 mm.