September weather forecast
Polonnaruwa, Sri Lanka

The first month of the autumn, September, is still a tropical month in Polonnaruwa, Sri Lanka, with temperature in the range of an average low of 24.1°C (75.4°F) and an average high of 33.9°C (93°F).

Temperature

In Polonnaruwa, Sri Lanka, the average high-temperature in September is relatively the same as in August - a still hot 33.9°C (93°F). In Polonnaruwa, the average low-temperature is 24.1°C (75.4°F).

Heat index

The average heat index in September is computed to be a blazing hot 45°C (113°F). Be wary: Heat exhaustion and heat cramps are highly anticipated. With continued activity, heatstroke is very likely.
Take into consideration that the heat index values are calculated for shade and light wind conditions. 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', 'feels like', 'felt air temperature', or 'apparent temperature', is a measure of how hot it feels when the actual air humidity is factored in. This effect is subjective, depending on the activity and individual's heat perception influenced by various reasons (wind, clothing, pregnancy). Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young children are generally more endangered than adults, as they usually less sweat. And also, due to larger skin surface relative to their small bodies and higher heat production as a result of their activity.
The human body cools itself through perspiration, as excessive warmth is removed from the body through sweat evaporation. High relative humidity reduces the evaporation rate, resulting in a lower heat removal rate from the body, causing the perception of being overheated. When heat gain surpasses the level the body can shed, body temperature begins to increase, and consequently, overheating and dehydration can occur, with varying severity.

Humidity

The months with the lowest humidity in Polonnaruwa are June through September, with an average relative humidity of 67%.

Rainfall

In September, in Polonnaruwa, Sri Lanka, the rain falls for 13.5 days. Throughout September, 53mm (2.09") of precipitation is accumulated. In Polonnaruwa, during the entire year, the rain falls for 196.8 days and collects up to 943mm (37.13") of precipitation.

Daylight

In Polonnaruwa, the average length of the day in September is 12h and 10min.
On the first day of September in Polonnaruwa, sunrise is at 05:57 and sunset at 18:14. On the last day of the month, sunrise is at 05:54 and sunset at 17:58 +0530.

Sunshine

In Polonnaruwa, Sri Lanka, the average sunshine in September is 10.9h.

UV index

February through October, with an average maximum UV index of 7, are months with the highest UV index. A UV Index estimate of 6 to 7 represents a high health vulnerability from unsafe exposure to UV radiation for the ordinary person.
Note: In September, the average maximum UV index of 7 translate into the following recommendations:
Take precautions against overexposure. Fair-skinned people may get burned in less than 20 minutes. Seek shade and minimize exposure to direct Sun in a period between 10 a.m. and 4 p.m. when UV radiation is most intense; keep in mind that shade structures like parasols or canopies do not provide perfect sun protection. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun.