September weather forecast
Ascension Island, Saint Helena, Ascension and Tristan da Cunha

With the advent of September, the weather remains similar to August with no significant drop in temperature. Sunshine hours reduce to 5.5h, making these days slightly shorter. Embrace the beauty of Ascension Island during exciting dawn treks and romantic sunset picnics. A relatively low rainfall ensures dry and comfortable outdoor activities. Sailing into October, anticipate similar weather patterns to continue, presented with a slight increase in sunshine duration.

Temperature

August through November bring Ascension Island's lowest average temperatures, reaching a high of 28°C (82.4°F).

Heat index

September's mean heat index is calculated to be a hot 31°C (87.8°F). Continuous activity in exposure could lead to a feeling of fatigue and heat cramps.
Consider that heat index readings are for situations in the shade and light wind. Under direct sunshine, the heat index values might be elevated by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'feels like' or 'felt air temperature', evaluates the perceived heat by adding the effect of moisture in the air. This effect is personal, shaped by the individual's physical activity and heat sensitivity, influenced by factors including wind, clothing, and metabolic variances. When directly under the sun, the weather's impact can intensify, possibly boosting the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are extremely significant for children. Young individuals usually face more risks than adults due to their lower sweat production. Their large skin surface area relative to their tiny bodies and high heat production from their activities adds to their risk.

Humidity

In Ascension Island, the average relative humidity in September is 69%.

Rainfall

In September, in Ascension Island, the rain falls for 2 days. Throughout September, 8mm (0.31") of precipitation is accumulated. Throughout the year, there are 30 rainfall days, and 142mm (5.59") of precipitation is accumulated.

Sea temperature

The months with the coldest seawater are September and October, with an average sea temperature of 24°C (75.2°F).
Note: Factoring in a person's dislike for cold, combined with conditions like sunshine, wind, and temperature, a dip in 24°C (75.2°F) waters might be satisfying. (It is worth noting that the Olympic swimming waters are maintained between 25°C (77°F) and 28°C (82.4°F).)

Daylight

In September, the average length of the day in Ascension Island is 12h and 4min.
On the first day of the month, sunrise is at 06:58 and sunset at 18:56. On the last day of September, in Ascension Island, Saint Helena, Ascension and Tristan da Cunha, sunrise is at 06:42 and sunset at 18:52 GMT.

Sunshine

In September, the average sunshine is 5.5h.

UV index

The months with the highest UV index in Ascension Island are January through April, September through December, with an average maximum UV index of 12. A UV Index reading of 11, and higher, represents an extreme health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: During September, 12 as the daily maximum UV index converts into the following advice:
Employ all crucial safeguards, unprotected skin could burn rapidly. Seek shade and limit direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Keep in mind that shade structures like parasols or canopies do not offer complete sun protection. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Avoid sunburn and the Sun's harmful radiation by applying a sunscreen of 30 SPF or more. It’s essential for your skin and immune system’s health. Alert! UV radiation becomes sharper due to reflections from sand and water.