September weather forecast
Gampaha, Sri Lanka

September witnesses the start of a transition period in Gampaha. While the rainfall drops to 153mm (6.02"), the wind strength sees a decrease, reflecting the pending end of the monsoon season. Cloud coverage remains relatively high, even as the number of sunlight hours starts picking up. September offers some respite from the heavy monsoons of the previous months, allowing life to return to routine. With the weather slowly settling, city dwellers start to experience the winds of change, as Gampaha preps itself for the upcoming dry spell.

Temperature

Gampaha's weather in September displays an average high-temperature of a still warm 29.5°C (85.1°F), showing minor disparity from August's 29.3°C (84.7°F). Night temperatures during September in Gampaha stabilize at an average of 25.2°C (77.4°F), closely mirroring the daytime temperatures.

Heat index

In September, the heat index is appraised at a torrid 36°C (96.8°F). Take greater precautions, heat exhaustion and heat cramps may be expected. Heatstroke could result from lengthy activity.
In terms of the heat index, values are set with light wind and shade conditions in mind. Being under direct sunlight might amplify the heat index by 15 Fahrenheit (8 Celsius) degrees.
Note: The heat index, also known as 'apparent temperature' or 'real feel', is what the temperature feels like to the human body when the air temperature is combined with the relative humidity. One's perception of temperature is subjective, varying based on their activity and individual heat perception, influenced by factors like wind, clothing, and metabolic variations. Be aware that direct exposure to sunlight increases heat impact and may raise the heat index by up to 15 Fahrenheit (8 Celsius) degrees. Heat index values are particularly important for children. Young individuals are generally in more danger than adults due to their lower capacity to sweat. Moreover, their large skin surface in relation to their small bodies and the increased heat generation from their activities makes them more vulnerable.
Perspiration is the human body's physiological response to high temperatures and is an attempt to lower body temperature through evaporation of sweat. When relative humidity is heightened, it slows the rate of evaporation, thereby decreasing the body's ability to shed heat and creating a sensation of overheating. Rising body temperatures resulting from an imbalance in heat absorption can lead to potential thermal issues.

Humidity

In Gampaha, the average relative humidity in September is 81%.

Rainfall

In Gampaha, in September, it is raining for 24.4 days, with typically 153mm (6.02") of accumulated precipitation. Throughout the year, in Gampaha, there are 265.4 rainfall days, and 1744mm (68.66") of precipitation is accumulated.

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 Gampaha, sunrise is at 05:57 and sunset at 18:01 +0530.

Sunshine

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

UV index

January through April, July, September, November and December, with an average maximum UV index of 7, are months with the highest UV index in Gampaha. A UV Index estimate of 6 to 7 represents a high health risk from unsafe exposure to UV radiation for the ordinary person.
Note: The daily maximum UV index of 7 in September interprets into the following advice:
Embrace precautions and observe sun safety norms. Evasion of sunburn is a necessity. Between 10 a.m. and 4 p.m., the Sun emits the most powerful UV radiation. Limit direct exposure to the Sun during these hours. On sunny days, it's ideal to wear sunglasses that filter out UVA and UVB rays.