September Weather in Chilaw, Sri Lanka

Last updated: August 31, 2025

In Chilaw, Sri Lanka, the average temperature in September hovers around 27°C (81°F), with a minimum of 25°C (77°F) and a maximum reaching 30°C (86°F). Expect ample rain, as the area receives about 199 mm (7.8 in) of precipitation over 26 days, contributing to a high average humidity level of 82%. Prepare for a warm and wet month!

September Temperature in Chilaw

In September in Chilaw, the average temperature is 27°C (81°F). The maximum can reach 30°C (86°F) and the minimum can be as low as 25°C (77°F). It's a perfect time to visit Chilaw for warm and pleasant weather!

September Weather in Chilaw: Daily Temperature Highs, Lows, and Averages

The chart illustrates September temperature patterns in Chilaw, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Chilaw, September typically has an average temperature of 27°C (81°F), with highs reaching up to 30°C (86°F) and lows dropping to around 25°C (77°F).

Data source: Temperature data for Chilaw generated using information from the Copernicus Climate Change Service.

September Precipitation in Chilaw

In Chilaw in September, the total precipitation amount is 199 mm (7.8 in) spread over 26 days.

September Precipitation Trends in Chilaw

The chart displays monthly precipitation patterns in Chilaw, with values for each month alongside September’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how September’s conditions compare to those of other months. In Chilaw, September typically receives around 199 mm (7.8 inches) of precipitation spread over approximately 26 days.

Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.

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Millimeters (mm) Inches (in)

September Humidity in Chilaw

In Chilaw in September humidity is 82%. With an average temperature of 27°C (81°F), this humidity feels like a heavy blanket wrapping around you, making outdoor activities feel more exhausting, and leaving you longing for the relief of air-conditioned spaces during your travels.

September Average Humidity in Chilaw

This chart illustrates the average monthly humidity levels in Chilaw, with September’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In September, average humidity in Chilaw is approximately 82%, offering insight into how humid the weather typically is during this month.

Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Chilaw

In Chilaw in September, the maximum UV index is 14, which corresponds to an extreme Exposure Category. The time to burn is just 10 minutes, so it's crucial to take precautions. For the detailed hourly UV index in Chilaw, you can check here.

Maximum UV Index Levels in Chilaw for September

The chart shows the monthly maximum UV Index (UVI) for Chilaw in September, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In September, the maximum UV index in Chilaw typically reaches 14, which falls under the extreme exposure category.

Data source: Chilaw September UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

Extreme (11+): Avoid the sun, stay in shade.
Very High (8-10): Limit sun exposure.
High (6-7): Use SPF 30+ and protective clothing.
Moderate (3-5): Midday shade recommended.
Low (0-2): No protection needed.

How September Weather in Chilaw Compares to Other Months

Weather in Chilaw varies notably across the year, with each month offering distinct climate conditions. This page compares September’s weather to other months in Chilaw, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Chilaw, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	27°C (80°F)	45 mm (1.8 inches)	77%	extreme
February Weather	27°C (82°F)	18 mm (0.7 inches)	73%	extreme
March Weather	28°C (83°F)	83 mm (3.3 inches)	74%	extreme
April Weather	28°C (83°F)	122 mm (4.8 inches)	74%	extreme
May Weather	28°C (83°F)	266 mm (10.5 inches)	76%	extreme
June Weather	28°C (83°F)	204 mm (8.0 inches)	82%	extreme
July Weather	28°C (82°F)	123 mm (4.8 inches)	82%	extreme
August Weather	27°C (81°F)	155 mm (6.1 inches)	83%	extreme
September Weather	27°C (81°F)	199 mm (7.8 inches)	82%	extreme
October Weather	27°C (81°F)	311 mm (12.2 inches)	81%	extreme
November Weather	27°C (81°F)	308 mm (12.1 inches)	80%	extreme
December Weather	27°C (81°F)	139 mm (5.5 inches)	80%	very high