September weather forecast
Siyambalapitiya, Sri Lanka

September, the first month of the autumn in Siyambalapitiya, is still a warm month, with an average temperature ranging between min 21°C (69.8°F) and max 29.4°C (84.9°F).

Temperature

The onset of September brings with it an average high-temperature of a still moderately hot 29.4°C (84.9°F), showing a negligible variation from the month before. Nighttime temperature experiences an average drop to a pleasant 21°C (69.8°F) in September.

Heat index

For September, the heat index is evaluated at a very hot 35°C (95°F). Implement additional preventive actions, heat cramps and heat exhaustion are potential hazards. Heatstroke could follow prolonged activity.
Know that the heat index computations account for shaded terrains and slight winds. The heat index has the potential to rise by 15 Fahrenheit (8 Celsius) degrees with direct sunshine exposure.
Note: The heat index, also known as 'feels like' or 'apparent temperature', is an estimation of the warmth sensation when considering humidity levels. A person's impression of weather can be swayed by numerous aspects, among them metabolic variations, pregnancy, and activity levels. The sun, when shining directly, can have a significant impact on the perceived temperature, increasing the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are quite important for babies and toddlers. Kids generally face higher risks than adults as they sweat less. Along with their large skin surface compared to their small bodies and higher heat production due to their activities, their vulnerability is increased.
When it comes to cooling down, the human body's primary method is through perspiration, making use of sweat evaporation to eliminate excess heat. When the relative humidity is high, the evaporation rate is reduced. The warmth is removed from the body at a lower rate, causing the body to retain more heat than it would in dry air. 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

In September, the average relative humidity is 77%.

Rainfall

In Siyambalapitiya, during September, the rain falls for 23.9 days and regularly aggregates up to 129mm (5.08") of precipitation. Throughout the year, in Siyambalapitiya, there are 278.9 rainfall days, and 1477mm (58.15") of precipitation is accumulated.

Daylight

In September, the average length of the day in Siyambalapitiya is 12h and 10min.
On the first day of the month, sunrise is at 06:02 and sunset at 18:17. On the last day of September, in Siyambalapitiya, sunrise is at 05:58 and sunset at 18:02 +0530.

Sunshine

In September, the average sunshine is 9.9h.

UV index

The months with the highest UV index are January through September, November and December, with an average maximum UV index of 6. A UV Index value of 6 to 7 symbolizes a high threat to health from unsafe exposure to UV radiation for average individuals.
Note: In September, the maximum UV index of 6 translates into these guidelines:
Avoid overexposure. Fair-skinned individuals can burn in under 20 minutes. Limit your direct sun exposure, especially between 10 a.m. and 4 p.m., when UV radiation is strongest. Shade structures might not provide complete sun protection. For optimum UV protection, wear sun-resistant attire complemented with a hat and quality shades.