September weather forecast
Kalutara, Sri Lanka

September arrives with marginal changes in temperature and an appreciable dip in rainfall. The highest temperature recorded is 28.8°C (83.8°F). As Kalutara slowly escapes the monsoon season, the humidity levels begin to steadily decrease, leading to a more comfortable atmospheric condition. The amount of sunshine begins to increase, slightly improving outdoor conditions than the preceding months. September signifies the absolute cessation of the monsoon period and the beginning of a drier spell.

Temperature

September's advent denotes a minor fluctuation in the average high-temperature to a still moderately hot 28.8°C (83.8°F) from August's 28.6°C (83.5°F). September nights in Kalutara, Sri Lanka, witness a slight temperature decrease, averaging at a still warm 25.2°C (77.4°F).

Heat index

In September, the heat index is estimated at a very hot 35°C (95°F). Additional precautions are required to avert heat cramps and heat exhaustion. Persistent activity may culminate in heatstroke.
Heat index specifics point out values are for conditions of shade and a slight breeze. Heat index values might soar by up to 15 Fahrenheit (8 Celsius) degrees with exposure to direct sunshine.
Note: The heat index, also known as 'feels like' or 'felt air temperature', is what the temperature feels like to the human body when the air temperature is combined with the relative humidity. The impact of weather is personal, differing among a variety of people based on differences in body mass, height, and the level of physical exertion. Direct exposure to sun rays can potentially augment the heat sensation, elevating the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are highly critical for babies and toddlers. 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.
Evaporating sweat, an outcome of perspiration, is key in assisting the human body to moderate its temperature. Relative humidity in excess curtails evaporation, therefore reducing heat dissipation from the body, leading to feelings of excess heat. Overheating dangers loom when the body's heat release mechanisms are overshadowed by excessive gain.

Humidity

In September, the average relative humidity is 82%.

Rainfall

In Kalutara, in September, during 26.3 rainfall days, 201mm (7.91") of precipitation is typically accumulated. Throughout the year, in Kalutara, there are 273.8 rainfall days, and 2059mm (81.06") of precipitation is accumulated.

Sea temperature

In September, the average sea temperature is 27.8°C (82°F).
Note: Water temperature between 25°C (77°F) and 29°C (84.2°F) is regarded as very warm and enjoyable by all. With these temperatures, water activities are pleasurable, without feeling uncomfortable for prolonged periods.

Daylight

In September, the average length of the day 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 Kalutara, Sri Lanka, sunrise is at 05:58 and sunset at 18:02 +0530.

Sunshine

The average sunshine in September is 7.6h.

UV index

January through April, July, September through December, with an average maximum UV index of 7, are months with the highest UV index in Kalutara. A UV Index estimate of 6 to 7 represents a high threat to health from exposure to the Sun's UV radiation for ordinary individuals.
Note: The UV index of 7 during September translates into the following guidance:
Embrace precautions and observe sun safety norms. Evasion of sunburn is a necessity. During the period from 10 a.m. to 4 p.m., UV radiation is highest. Try to avoid direct sunlight during these hours. Safeguard your eyes, ears, and face from sun rays with the aid of a wide-brim hat. Alert! UV radiation becomes sharper due to reflections from sand and water.