Last updated: March 2, 2024
The weather in Heidelberg, United States, during September is characterized by an average temperature of 26°C (78°F). Highs can soar to 36°C (96°F), while lows may dip to 15°C (60°F). Typically, the humidity level in Heidelberg throughout September hovers around 80%.
Minimum temperature
Average temperature
Maximum temperature
Humidity
In September, Heidelberg averages 97 mm (3.8 inches) of rainfall, typically over the course of 10 rainy days. The month enjoys an average of 12 hours 18 minutes of daylight, with the sun shining for approximately 9 hours 25 minutes each day. Additionally, there is a 47% probability of sunny days during this period.
Precipitation
Rainy days
Sunshine hours
Chance of sun
In September, the UV Index in Heidelberg reaches a maximum of 10, 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 | 3 | 5 | 8 | 9 | 10 | 9 | 7 | 4 | 2 | 1 | 1 |
| Exposure | Low | Moderate | VeryHigh | High | Moderate | Low | |||||||
| Time to burn | 45 min | 30 min | 15 min | 25 min | 30 min | 45 min | |||||||