Last updated: March 2, 2024
The weather in Jamestown, Saint Helena, Ascension and Tristan da Cunha, during September is characterized by an average temperature of 20°C (67°F). Highs can soar to 20°C (69°F), while lows may dip to 19°C (66°F). Typically, the humidity level in Jamestown throughout September hovers around 78%.
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Average temperature
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Humidity
In September, Jamestown averages 13 mm (0.5 inches) of rainfall, typically over the course of 1 rainy days. The month enjoys an average of 12 hours 0 minutes of daylight, with the sun shining for approximately 8 hours 28 minutes each day. Additionally, there is a 26% probability of sunny days during this period.
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Chance of sun
In September, the UV Index in Jamestown reaches a maximum of 11, indicating a level of Extreme exposure. The most intense UV radiation typically occurs between 12:00 and 14:00, during which unprotected skin may burn in as little as 10 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 | 2 | 5 | 8 | 10 | 11 | 11 | 8 | 5 | 3 | 1 | 1 | 0 |
| Exposure | Low | Moderate | VeryHigh | Extreme | VeryHigh | Moderate | Low | ||||||
| Time to burn | 45 min | 30 min | 15 min | 10 min | 15 min | 30 min | 45 min | ||||||