Last updated: August 22, 2025
In September, the average temperature in St Helena, Australia is a mild 12°C (54°F). Expect temperatures to vary, with a minimum hitting 1°C (33°F) and a maximum reaching up to 27°C (81°F). During this period, precipitation averages 64 mm (2.5 in) over about 12 days, combined with an average humidity of 72%. Enjoy a blend of refreshing coolness and occasional warmth!
In September in St Helena, the average temperature is 12°C (54°F), with maximums reaching up to 27°C (81°F) and minimums dropping as low as 1°C (33°F). This makes St Helena a great destination for travelers seeking mild weather and the opportunity to enjoy both warm days and cool evenings.
In St Helena in September, the total precipitation amount is 64 mm (2.5 in) over the course of 12 days.
In St Helena in September, humidity is 72%. With an average temperature of 12°C (54°F), this humidity feels like a damp chill that wraps around you, making outdoor excursions a bit uncomfortable. You may find yourself reaching for an extra layer as the moisture in the air adds to the coolness, prompting travelers to seek out sheltered spots to enjoy the scenery.
In St Helena in September, the maximum UV index is 7, which corresponds to the high Exposure Category. This means that the time to burn is approximately 25 minutes. For more detailed information, you can check the Hourly UV Index in St Helena.
UV Risk Categories
Weather in St Helena varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in St Helena, focusing on differences in temperature, rainfall, humidity, and UV levels.
| Temperature | Precipitation | Humidity | UV | |
|---|---|---|---|---|
| January Weather | 21°C (70°F) | 42 mm (1.6 inches) | 43% | extreme |
| February Weather | 19°C (67°F) | 44 mm (1.7 inches) | 49% | extreme |
| March Weather | 19°C (66°F) | 40 mm (1.6 inches) | 60% | extreme |
| April Weather | 15°C (60°F) | 51 mm (2.0 inches) | 71% | high |
| May Weather | 12°C (54°F) | 57 mm (2.2 inches) | 79% | moderate |
| June Weather | 10°C (50°F) | 54 mm (2.1 inches) | 81% | moderate |
| July Weather | 10°C (49°F) | 46 mm (1.8 inches) | 83% | moderate |
| August Weather | 10°C (50°F) | 58 mm (2.3 inches) | 79% | moderate |
| September Weather | 12°C (54°F) | 64 mm (2.5 inches) | 72% | high |
| October Weather | 14°C (58°F) | 74 mm (2.9 inches) | 61% | very high |
| November Weather | 17°C (62°F) | 58 mm (2.3 inches) | 59% | extreme |
| December Weather | 18°C (65°F) | 74 mm (2.9 inches) | 50% | extreme |