September weather forecast
Mahadeniya, Sri Lanka

The first month of the autumn, September, is also a moderately hot month in Mahadeniya, Sri Lanka, with temperature in the range of an average low of 24.9°C (76.8°F) and an average high of 29.1°C (84.4°F).

Temperature

The transition into September is marked with an average high-temperature of a still warm 29.1°C (84.4°F), showing an insignificant shift from August's 28.9°C (84°F). Night temperatures in September exhibit a subtle decrease, settling at an average of 24.9°C (76.8°F).

Heat index

September's mean heat index is estimated at a very hot 35°C (95°F). Take additional safety steps, risk of heat exhaustion and heat cramps is notable. Prolonged activity may cause heatstroke.
The metrics for the heat index are tailored for both shady environments and light winds. Facing direct sunlight may hike up the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'felt air temperature' or 'real feel', evaluates the perceived heat by adding the effect of moisture in the air. The influence of weather is personal, differing among a variety of individuals based on differences in body mass, stature, and the level of physical activity. Considering the impact of direct sunlight, it's possible for the heat index to surge by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values hold particular importance for children. Young people are generally more susceptible than adults because they perspire less. Furthermore, their proportionally larger skin surface to their petite bodies and the increased heat output from their actions add to the risk.
The human body cools itself through perspiration, as excessive warmth is removed from the body through sweat evaporation. When air moisture content is high, the cooling process through evaporation is not as efficient, leading to an ineffective body cooling process and a feeling of overheating. Accumulating heat beyond the body's cooling measures leads to rising temperatures and potential ailments.

Humidity

The average relative humidity in September is 81%.

Rainfall

In Mahadeniya, in September, during 26.9 rainfall days, 206mm (8.11") of precipitation is typically accumulated. Throughout the year, there are 289.4 rainfall days, and 2262mm (89.06") of precipitation is accumulated.

Daylight

In September, the average length of the day in Mahadeniya, Sri Lanka, is 12h and 10min.
On the first day of the month, sunrise is at 06:01 and sunset at 18:16. On the last day of September, in Mahadeniya, sunrise is at 05:57 and sunset at 18:00 +0530.

Sunshine

In September, the average sunshine in Mahadeniya is 7.4h.

UV index

The months with the highest UV index in Mahadeniya are January through April, July, September, November and December, with an average maximum UV index of 7. A UV Index of 6 to 7 symbolizes a high health vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.
Note: The maximum UV index, 7 during September, leads to the following recommendations:
Exercise precautions and adapt sun safety practices. Defence against skin and eye affliction is paramount. 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. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.