Last updated: March 2, 2024
The weather in Santa Rosa, United States, during September is characterized by an average temperature of 20°C (69°F). Highs can soar to 37°C (99°F), while lows may dip to 9°C (49°F). Typically, the humidity level in Santa Rosa throughout September hovers around 68%.
Minimum temperature
Average temperature
Maximum temperature
Humidity
In September, Santa Rosa averages 2 mm (0.1 inches) of rainfall, typically over the course of 0 rainy days. The month enjoys an average of 12 hours 22 minutes of daylight, with the sun shining for approximately 10 hours 24 minutes each day. Additionally, there is a 76% probability of sunny days during this period.
Precipitation
Rainy days
Sunshine hours
Chance of sun
In September, the UV Index in Santa Rosa reaches a maximum of 9, indicating a level of VeryHigh exposure. The most intense UV radiation typically occurs between 13:00 and 15:00, during which unprotected skin may burn in as little as 15 minutes.
| 07:00 | 08:00 | 09:00 | 10:00 | 11:00 | 12:00 | 13:00 | 14:00 | 15:00 | 16:00 | 17:00 | 18:00 | 19:00 | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| UVI | 1 | 1 | 2 | 4 | 6 | 8 | 9 | 8 | 6 | 4 | 2 | 1 | 1 |
| Exposure | Low | Moderate | High | VeryHigh | High | Moderate | Low | ||||||
| Time to burn | 45 min | 30 min | 25 min | 15 min | 25 min | 30 min | 45 min | ||||||