September weather forecast
Chilaw, Sri Lanka

September, the first month of the autumn in Chilaw, is still a warm month, with an average temperature fluctuating between 29.5°C (85.1°F) and 25.2°C (77.4°F).

Temperature

The advent of September reveals an average high-temperature of a still warm 29.5°C (85.1°F), showing minimal difference from the prior month. September's average low temperature is a still moderately hot 25.2°C (77.4°F), displaying a subtle drop from its daily peak.

Heat index

In September, the average heat index is appraised at a sweltering 36°C (96.8°F). Undertake additional safety actions, risk of heat cramps and heat exhaustion is significant. Persistent activity may induce heatstroke.
Always consider that heat index estimations are for light winds and places in the shade. Direct sunlight might lead to a heat index increase by up to 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', blends air temperature and moisture content to represent the felt temperature to humans. Elements such as metabolic variations, pregnancy, and physical exertion can influence one's weather perception. Keep in mind that direct sunshine exposure can amplify the weather's effects, possibly increasing the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values remain especially vital for babies and toddlers. Children usually face more risks than adults as their ability to sweat is less. Additionally, their larger skin surface in relation to their petite bodies and higher heat output due to their activities increases their vulnerability.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. An increase in relative humidity retards evaporation, subsequently reducing the body's heat removal rate and leading to a sensation of being overly warm. Excessive heat that's not properly managed leads to increased body temperatures and resultant health issues.

Humidity

The average relative humidity in September is 81%.

Rainfall

In Chilaw, in September, it is raining for 24.4 days, with typically 153mm (6.02") of accumulated precipitation. In Chilaw, during the entire year, the rain falls for 265.4 days and collects up to 1744mm (68.66") of precipitation.

Sea temperature

In September, the average sea temperature in Chilaw is 27.6°C (81.7°F).
Note: Water activities including swimming and diving are pleasurable in temperatures between 25°C (77°F) and 29°C (84.2°F), ensuring comfort and enjoyment for extended time frames.

Daylight

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

Sunshine

In September, the average sunshine in Chilaw is 7.7h.

UV index

The months with the highest UV index are January through April, July, September, November and December, with an average maximum UV index of 7. A UV Index estimate of 6 to 7 represents a high threat to health from unprotected exposure to Sun's UV rays for average individuals.
Note: In September, an average UV index of 7 transforms into the following instructions:
Guard against overexposure. Protection from sun-induced harm is essential. Seek shade and limit direct sun exposure between 10 a.m. and 4 p.m., the peak period for UV radiation. Keep in mind that shade structures like parasols or canopies do not offer complete sun protection. Sunglasses that ward off UVA and UVB rays play a pivotal role in reducing solar eye damage. Caution! The Sun's UV intensity grows with reflections off sand and water.