September Weather in Saint Helena, United States

Last updated: June 24, 2025

In Saint Helena, United States, the average temperature in September is a pleasant 21°C (71°F). However, temperatures can fluctuate significantly, ranging from a crisp 7°C (46°F) to a scorching 43°C (109°F). Fortunately, the region experiences minimal precipitation, with just 2 mm (0.1 in) falling over 0 days. This lovely climate is complemented by an average humidity of 68%, creating a comfortable atmosphere for all.

September Temperature in Saint Helena

In September in Saint Helena, the average temperature is 21°C (71°F), with maximums reaching up to 43°C (109°F) and minimums dropping as low as 7°C (46°F). This range makes it important for travelers to pack both light clothing for warm days and warmer layers for cooler nights.

September Weather in Saint Helena: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Saint Helena, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Saint Helena, September typically has an average temperature of 21°C (71°F), with highs reaching up to 43°C (109°F) and lows dropping to around 7°C (46°F).

Data source: Temperature data for Saint Helena generated using information from the Copernicus Climate Change Service.

September Precipitation in Saint Helena

In Saint Helena in September, the precipitation amount is 2 mm (0.1 in) during a span of 0 days.

September Precipitation Trends in Saint Helena

The chart displays monthly precipitation patterns in Saint Helena, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Saint Helena, September typically receives around 2 mm (0.1 inches) of precipitation spread over approximately 0 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Saint Helena

In Saint Helena in September, humidity is 68%. With an average temperature of 21°C (71°F), this humidity feels like a warm embrace, making traveling a bit sticky but also inviting for leisurely strolls and outdoor adventures.

September Average Humidity in Saint Helena

This chart illustrates the average monthly humidity levels in Saint Helena, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Saint Helena is approximately 68%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Saint Helena

In Saint Helena in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Saint Helena.

Maximum UV Index Levels in Saint Helena for September

The chart shows the monthly maximum UV Index (UVI) for Saint Helena in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Saint Helena typically reaches 9, which falls under the very high exposure category.

Data source: Saint Helena September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How September Weather in Saint Helena Compares to Other Months

Weather in Saint Helena varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Saint Helena, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Saint Helena, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	9°C (49°F)	137 mm (5.4 inches)	86%	moderate
February Weather	10°C (51°F)	141 mm (5.6 inches)	84%	moderate
March Weather	11°C (53°F)	92 mm (3.6 inches)	83%	high
April Weather	15°C (59°F)	39 mm (1.5 inches)	80%	very high
May Weather	18°C (64°F)	23 mm (0.9 inches)	80%	very high
June Weather	22°C (72°F)	2 mm (0.1 inches)	76%	extreme
July Weather	23°C (74°F)	0 mm (0.0 inches)	70%	extreme
August Weather	23°C (73°F)	0 mm (0.0 inches)	66%	very high
September Weather	21°C (71°F)	2 mm (0.1 inches)	68%	very high
October Weather	18°C (64°F)	38 mm (1.5 inches)	72%	high
November Weather	12°C (55°F)	51 mm (2.0 inches)	84%	moderate
December Weather	9°C (49°F)	95 mm (3.7 inches)	84%	moderate