September weather forecast
Repulse Bay, Hong Kong

The first month of the autumn, September, is still a warm month in Repulse Bay, Hong Kong, with temperature in the range of an average high of 29.6°C (85.3°F) and an average low of 26.5°C (79.7°F).

Temperature

September's advent notes a subtle adjustment in average high-temperature to a moderately hot 29.6°C (85.3°F) from August. Consistently, Repulse Bay reports average nighttime temperatures of 26.5°C (79.7°F) during September, a marginal step down from its daytime highs.

Heat index

In September, the average heat index is computed to be a very hot 36°C (96.8°F). Take extra precautions, as heat cramps and heat exhaustion are possible. Sustained activity may result in heatstroke.
One should consider that heat index numbers are for shaded settings and light wind. Exposure to direct sunshine can increase heat index values by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'felt air temperature', is an index that combines air temperature and relative humidity to determine the human-perceived temperature equivalent. The perception of temperature can be subjective, varying based on activity and individual heat sensitivity, influenced by factors like wind, attire, and metabolic variations. Direct sun rays have a notable impact on perceived temperature, which can raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Juveniles often do not understand the need to recuperate and rehydrate. Thirst is a delayed symptom of dehydration - hence, it is vital to maintain hydration, particularly during ongoing physical activities.
The body's natural response to excessive warmth is perspiration, as it allows for cooling through sweat evaporation. With high air temperature and humidity (high heat index) conditions, sweat production is restricted, leading to an amplified perception of heat. Overheating risks increase with rising body temperatures, especially if heat release isn't efficient.

Humidity

In September, the average relative humidity in Repulse Bay is 77%.

Rainfall

In September, the rain falls for 22.7 days. Throughout September, 155mm (6.1") of precipitation is accumulated. Throughout the year, in Repulse Bay, there are 224.5 rainfall days, and 1264mm (49.76") of precipitation is accumulated.

Daylight

In September, the average length of the day is 12h and 17min.
On the first day of September in Repulse Bay, sunrise is at 06:06 and sunset at 18:40. On the last day of the month, sunrise is at 06:14 and sunset at 18:11 HKT.

Sunshine

The average sunshine in September in Repulse Bay is 8.4h.

UV index

May through September, with an average maximum UV index of 7, are months with the highest UV index. A UV Index of 6 to 7 symbolizes a high health risk from exposure to the Sun's UV rays for the average person.
Note: In September, the maximum UV index of 7 suggests this advice:
Incorporate safeguards and honour sun safety principles. Protection from skin and eye damage is obligatory. Stay in the shade and avoid direct Sun exposure from 10 a.m. to 4 p.m., a period when UV radiation is particularly strong, noting that parasols or canopies may not offer total sun protection. Shield yourself from the harmful effects of UV radiation with sun-protective attire, a hat, and quality sunglasses.