Average temperature in September is 18.9 °C
Average daytime temperature is 24 °C
Average night temperature is 15 °C
Absolute maximum temperature: 33.6 °C
Absolute minimum temperature: 8.4 °C
Number of sunny days: 13
Number of rainy days: 17
Number of snow days:
Precipitation sum: 62 mm
* Weather data for Watertown 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 | 26.6 | 30.8 | 33.6 | 32.9 | 31.6 | 27.8 | 22.4 | 19 | 22.8 | 25.1 | 20.4 | 19.8 | 17.8 | 21 | 24.3 | 23.7 | 20.8 | 20.4 | 20.3 | 25.6 | 24.1 | 25.3 | 25.9 | 22.4 | 22.7 | 20.7 | 20.2 | 20.8 | 23.1 | 27.6 |
| Apparent max temperature | 26 | 30.6 | 34.1 | 33.9 | 32 | 29.2 | 23.8 | 17.8 | 23.4 | 26.1 | 19.9 | 18.7 | 15.9 | 20.9 | 22.6 | 24.2 | 18.4 | 20.7 | 19.2 | 26.6 | 24.5 | 24.9 | 24.5 | 20.8 | 22.8 | 20.3 | 19.2 | 21.3 | 23.1 | 29.1 |
| Mean temperature | 19 | 22.7 | 26.1 | 26.6 | 27.2 | 24.3 | 18.3 | 16.7 | 15.7 | 18.5 | 17.3 | 15 | 13.9 | 13.8 | 16.7 | 19.1 | 16.8 | 14.7 | 15.8 | 19.4 | 19.7 | 20.5 | 21.4 | 18.5 | 18.6 | 18.2 | 17.4 | 17.4 | 16.5 | 19.9 |
| Apparent mean temperature | 12.6 | 16.8 | 19.1 | 21.5 | 25.7 | 22.4 | 12.6 | 13.9 | 8.7 | 12.6 | 14 | 9.7 | 8.5 | 6.6 | 9.4 | 13.9 | 13.4 | 9.6 | 11.6 | 14.9 | 17.1 | 16.9 | 17.4 | 13.4 | 15.8 | 16.3 | 15.7 | 14 | 10.8 | 15.4 |
| Minimum temperature | 13.2 | 17.7 | 20.7 | 20.5 | 23.6 | 20.6 | 14.5 | 15.1 | 9.6 | 13.2 | 14.6 | 10.8 | 9.7 | 8.4 | 11.2 | 14.9 | 14.3 | 10 | 13 | 15.7 | 16.3 | 16.6 | 18.7 | 16 | 16.9 | 16.8 | 15.9 | 13.9 | 11.4 | 15.4 |
| Apparent min temperature | 18.3 | 22.1 | 25.4 | 27.4 | 28.3 | 26.2 | 17.3 | 15.8 | 15.5 | 18.3 | 16.8 | 14 | 12.5 | 12.9 | 15.1 | 18.3 | 15.8 | 14.2 | 14.6 | 19.2 | 20.8 | 20.6 | 20.4 | 16.5 | 17.9 | 17.8 | 17 | 17.5 | 16.5 | 20.3 |
| 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) | 13.2 | 13.2 | 13.1 | 13.1 | 13 | 13 | 12.9 | 12.9 | 12.8 | 12.8 | 12.7 | 12.7 | 12.6 | 12.6 | 12.5 | 12.5 | 12.4 | 12.4 | 12.3 | 12.3 | 12.2 | 12.2 | 12.1 | 12.1 | 12 | 12 | 11.9 | 11.9 | 11.8 | 11.8 |
| Sunshine duration (h) | 12.1 | 12 | 12 | 12 | 10.8 | 10.8 | 2.3 | 1.8 | 11.5 | 9.9 | 7.9 | 11.7 | 9.2 | 11.7 | 11.6 | 7.6 | 8.8 | 9.2 | 6.6 | 7.9 | 4.9 | 10.8 | 10.2 | 6.4 | 6.7 | 7.7 | 6 | 6.6 | 8 | 10.7 |
| Precipitation (mm) | 0 | 0 | 0 | 0 | 0 | 7.8 | 0.8 | 0 | 0 | 1.1 | 10.8 | 0 | 2.1 | 0 | 0 | 0.2 | 2.9 | 0 | 4.8 | 0.2 | 0.3 | 0.3 | 0.3 | 0.5 | 13.9 | 10.5 | 5.6 | 0.3 | 0 | 0 |
| Precipitation hours | 0 | 0 | 0 | 0 | 0 | 11 | 3 | 0 | 0 | 3 | 8 | 0 | 9 | 0 | 0 | 1 | 8 | 0 | 5 | 1 | 1 | 3 | 1 | 2 | 10 | 14 | 17 | 3 | 0 | 0 |
| Wind speed (m/s) | 15.9 | 20.5 | 20.1 | 18.5 | 24.8 | 19.8 | 20.3 | 11.9 | 8 | 11.7 | 14 | 11.8 | 12.9 | 8.7 | 16.4 | 12.3 | 17.3 | 8.8 | 18.1 | 16 | 19 | 24.1 | 19.9 | 19.1 | 21.9 | 21.7 | 20.2 | 14.6 | 12.3 | 16.6 |
In September 2023, the highest daytime temperature in Watertown was 33.6°C.
While the minimum temperature at night dropped to 8.4°C.
The average nighttime and daytime temperatures during September in Watertown are 15°C and 24°C respectively.
The precipitation sum in September is about 62 mm.