Last updated: March 2, 2024
The weather in Fullerton, United States, during September is characterized by an average temperature of 22°C (72°F). Highs can soar to 33°C (93°F), while lows may dip to 16°C (61°F). Typically, the humidity level in Fullerton throughout September hovers around 68%.
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Humidity
In September, Fullerton averages 3 mm (0.1 inches) of rainfall, typically over the course of 0 rainy days. The month enjoys an average of 12 hours 19 minutes of daylight, with the sun shining for approximately 10 hours 32 minutes each day. Additionally, there is a 68% probability of sunny days during this period.
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Chance of sun
In September, the UV Index in Fullerton reaches a maximum of 10, indicating a level of VeryHigh exposure. The most intense UV radiation typically occurs between 12:00 and 14:00, 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 | 10 | 10 | 9 | 6 | 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 | |||||||