September weather forecastHa Long, Vietnam

Weather in September

September in Ha Long manifests the gradual transition from summer to autumn. Though the rainfall starts to recede to 232mm (9.13"), the level remains significant compared to the rest of the year. The decrease of rainfall does not compromise the charm of Ha Long. With cooling temperatures and a slightly reduced rainfall, September leans gradually towards a more comfortable climate. The changing colors of the city's natural landscape provide an enchanting backdrop for explorers.

Temperature

September's presence records an average high-temperature of a still tropical 30.9°C (87.6°F), closely mirroring August's climate. Throughout September, Ha Long's nights cool down to an average of 23.3°C (73.9°F).

Heat index

September's mean heat index is estimated at a scorching 42°C (107.6°F). Implement enhanced safety actions, heat cramps and heat exhaustion could occur. Sustained activity might result in heatstroke.
Remember that heat index calculations are made for conditions in the shade with light wind. If directly exposed to the sun, the heat index could rise by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'felt air temperature', is a composite of temperature and humidity figures to convey how warm it feels. The influence of weather is personal, differing among individuals based on variations in body mass, stature, and the degree of physical exertion. It is essential to be conscious of the fact that direct sunlight can intensify the felt heat, leading to an elevation in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular significance for children. Children often lack awareness of the importance of taking breaks and rehydrating. The feeling of thirst is a late indication of dehydration, so maintaining hydration, especially during long periods of physical activity, is critical.
Evaporating sweat is a key way the human body dispels excessive warmth, all thanks to the process of perspiration. In circumstances of high air temperature and humidity (high heat index), the body's perspiration is restricted, heightening the feeling of warmth. Temperature imbalances caused by excessive heat retention can trigger heat-related maladies.

Humidity

The months with the highest humidity are August and September, with an average relative humidity of 83%.

Rainfall

In September, the rain falls for 22.9 days. Throughout September, 232mm (9.13") of precipitation is accumulated. In Ha Long, during the entire year, the rain falls for 237.1 days and collects up to 1472mm (57.95") of precipitation.

Sea temperature

In September, the average sea temperature in Ha Long is 29.3°C (84.7°F).
Note: Temperatures between 25°C (77°F) and 29°C (84.2°F) are excellent for swimming, diving, and other water activities, providing comfort and enjoyment for extended periods without discomfort.

Daylight

The average length of the day in September is 12h and 16min.
On the first day of the month, sunrise is at 05:35 and sunset at 18:08. On the last day of September, sunrise is at 05:42 and sunset at 17:40 +07.

Sunshine

In Ha Long, the average sunshine in September is 8.1h.

UV index

The average daily maximum UV index in September is 6. A UV Index reading of 6 to 7 represents a high threat to health from unsafe exposure to UV radiation for ordinary individuals.
Note: In September, a daily UV index of 6 turns into the following recommendations:
Elude overexposure. Fair-skinned people could get burnt in less than 20 minutes. Be aware that the sun's UV radiation is strongest between 10 a.m. and 4 p.m. and try to reduce direct sun exposure during this period as much as possible. Loose clothes with a tight weave are optimal for safeguarding yourself against the Sun's rays. Attention! UV strength is notably upped by the reflection of sand and water.