September weather forecast
Chennai, India

Signifying the gradual withdrawal of monsoon, September weather in Chennai is characterized by plummeting rainfall, yet the soggy condition from August stays, as reflected in a substantial 98mm (3.86") rainfall. The decline in temperature starts to soften, offering respite to the residents from the intense humidity. Daylight starts to contract but paired with receding cloud cover, the sky often presents beautiful sunset vistas. The wind lags slightly, signalling the eventual cessation of monsoon; however, temperatures on land and at sea remain pleasantly in sync. Even as disruption looms for the monsoon, September in Chennai retains the city's characteristic warm and wet climate.

Temperature

Chennai, India, marks the onset of September with an average high-temperature of a still hot 31.6°C (88.9°F), a subtle shift from August's 32.3°C (90.1°F). Chennai's evenings during September maintain an average temperature of 27.3°C (81.1°F), aligning closely with the daytime temperatures.

Heat index

The heat index value for September is evaluated at an extremely hot 40°C (104°F). Undertake additional precautions, heat cramps and heat exhaustion could happen. Heatstroke could occur from sustained activity.
Keep in mind the heat index values are meant for areas in shade and with light wind. Heat index values can rise by 15 Fahrenheit (8 Celsius) degrees when in direct sunlight.
Note: The heat index, also known as 'feels like' or 'apparent temperature', is a calculated temperature value of how hot it feels when the moisture in the air is factored in. This effect tends to be personal, with the weather perception differing among individuals due to variations in body mass, height, and exertion. When exposed to direct sunlight, it's possible for the heat index to increase by as much as 15 Fahrenheit (8 Celsius) degrees. Heat index values remain especially vital for babies and toddlers. Young ones regularly neglect the requirement for rest and fluid replenishment. Thirst is a late stage of dehydration - so, it is necessary to keep hydrated, particularly during extended periods of physical exertion.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. Under conditions of increased relative humidity, the evaporation rate lessens, causing the body to retain more heat than under less humid conditions. Accumulating more heat than the body can dissipate leads to an uptick in body temperature, with potential heat stress consequences.

Humidity

The average relative humidity in September is 72%.

Rainfall

In Chennai, in September, it is raining for 23.1 days, with typically 98mm (3.86") of accumulated precipitation. In Chennai, during the entire year, the rain falls for 157.6 days and collects up to 823mm (32.4") of precipitation.

Sea temperature

In Chennai, India, in September, the average water temperature is 29.3°C (84.7°F).
Note: For water activities like swimming, diving, and more, temperatures ranging between 25°C (77°F) and 29°C (84.2°F) offer superior comfort and enjoyment for lengthy durations.

Daylight

The average length of the day in September in Chennai is 12h and 12min.
On the first day of September, sunrise is at 5:57 am and sunset at 6:19 pm. On the last day of the month, sunrise is at 5:58 am and sunset at 5:59 pm IST.

Sunshine

The average sunshine in September is 10.7h.

UV index

In September, the average daily maximum UV index is 7. A UV Index estimate of 6 to 7 represents a high threat to health from exposure to the Sun's UV rays for ordinary individuals.
Note: An average UV index of 7 in September transforms into this advice:
Sidestep overexposure. Individuals with fair complexions risk burning in fewer than 20 minutes. UV radiation from the sun is at its strongest between 10 a.m. and 4 p.m. Try to limit direct exposure during these hours. For excellent sun protection for the eyes, ears, face, and neck, consider a wide-brim hat. Notice! Sand and water reflections contribute to a stronger UV exposure.