September weather forecast
Sirimalwatta, Sri Lanka

September, the first month of the autumn in Sirimalwatta, is also a moderately hot month, with an average temperature ranging between max 29.5°C (85.1°F) and min 21.1°C (70°F).

Temperature

The advent of September presents an average high-temperature of a still moderately hot 29.5°C (85.1°F), maintaining a close correlation with the preceding month. In September, the temperature drops to an average of 21.1°C (70°F) at night.

Heat index

Throughout September, the heat index is evaluated at a sweltering 35°C (95°F). Adopt additional preventive measures, heat cramps and heat exhaustion are potential outcomes. Prolonged activity may trigger heatstroke.
Understanding the heat index involves considering values for shaded locales with light wind. Being exposed to direct sunshine might trigger a heat index increase by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'real feel' or 'apparent temperature', arises from combining readings of air temperature and relative moisture content. Factors such as metabolic variations, being pregnant, and physical activity can impact an individual's weather perception. Realize that direct exposure to sunlight can augment the felt heat, leading to a potential increase in the heat index by 15 Fahrenheit (8 Celsius) degrees. Heat index values are especially crucial for babies and toddlers. Children often overlook the need for breaks and fluid intake. Thirst is a late-stage sign of dehydration - hence, it is necessary to stay hydrated, especially during extended periods of physical activities.
Evaporating sweat, thanks to perspiration, acts as a natural air conditioner for the human body. Greater relative humidity lessens the rate of evaporation, thus decreasing the body's heat dispersal, which gives rise to a sensation of overheating. Potential thermal conditions emerge as the body's heat gain outpaces its cooling mechanisms.

Humidity

In Sirimalwatta, Sri Lanka, the average relative humidity in September is 77%.

Rainfall

In Sirimalwatta, during September, the rain falls for 23.4 days and regularly aggregates up to 118mm (4.65") of precipitation. In Sirimalwatta, Sri Lanka, during the entire year, the rain falls for 278.4 days and collects up to 1466mm (57.72") of precipitation.

Daylight

In Sirimalwatta, the average length of the day in September is 12h and 10min.
On the first day of the month, sunrise is at 05:59 and sunset at 18:14. On the last day of September, in Sirimalwatta, sunrise is at 05:55 and sunset at 17:59 +0530.

Sunshine

In Sirimalwatta, the average sunshine in September is 10.3h.

UV index

January through September, November and December, with an average maximum UV index of 6, are months with the highest UV index in Sirimalwatta. A UV Index value of 6 to 7 symbolizes a high health hazard from exposure to the Sun's UV rays for the ordinary person.
Note: In September, the UV index of 6 transforms into the following advice:
Follow precautions and abide by sun safety rules. Deterrence of sunburn is imperative. 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. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation.