September Weather in Mersak, Indonesia

Last updated: August 23, 2025

In Mersak, Indonesia, the average temperature in September is a pleasant 18°C (65°F), with a minimum of 13°C (55°F) and a maximum reaching 27°C (80°F). Expect about 456 mm (18.0 in) of precipitation over 27 days, resulting in an average humidity of 84%, making it a notably humid month.

September Temperature in Mersak

In September in Mersak, the average temperature is 18°C (65°F). Maximums can reach 27°C (80°F) and minimums can be as low as 13°C (55°F). This pleasant climate makes it an ideal destination for travelers seeking mild weather and outdoor activities.

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

The chart illustrates September temperature patterns in Mersak, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Mersak, September typically has an average temperature of 18°C (65°F), with highs reaching up to 27°C (80°F) and lows dropping to around 13°C (55°F).

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

September Precipitation in Mersak

In Mersak in September, the precipitation amount is 456 mm (18.0 in) spread over 27 days, indicating a significant amount of rainfall during that period.

September Precipitation Trends in Mersak

The chart displays monthly precipitation patterns in Mersak, 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 Mersak, September typically receives around 456 mm (18.0 inches) of precipitation spread over approximately 27 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 Mersak

In Mersak in September, humidity is 84%. With an average temperature of 18°C (65°F), this humidity feels like a thick blanket enveloping you, making travel feel heavy and slightly uncomfortable as the air clings to your skin and limits your breath.

September Average Humidity in Mersak

This chart illustrates the average monthly humidity levels in Mersak, 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 Mersak is approximately 84%, 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 Mersak

In Mersak in September, the maximum UV index reaches an alarming 15, which falls into the extreme Exposure Category. With a time to burn of just 10 minutes, it's crucial to take precautions. For detailed information, you can check the Hourly UV Index in Mersak.

Maximum UV Index Levels in Mersak for September

The chart shows the monthly maximum UV Index (UVI) for Mersak 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 Mersak typically reaches 15, which falls under the extreme exposure category.

Data source: Mersak 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 Mersak Compares to Other Months

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

This table compares monthly weather conditions in Mersak, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	18°C (66°F)	318 mm (12.5 inches)	79%	extreme
February Weather	19°C (66°F)	292 mm (11.5 inches)	73%	extreme
March Weather	19°C (66°F)	445 mm (17.5 inches)	74%	extreme
April Weather	19°C (66°F)	557 mm (21.9 inches)	73%	extreme
May Weather	19°C (67°F)	502 mm (19.8 inches)	77%	extreme
June Weather	19°C (66°F)	297 mm (11.7 inches)	79%	extreme
July Weather	19°C (66°F)	296 mm (11.7 inches)	77%	extreme
August Weather	19°C (66°F)	327 mm (12.9 inches)	81%	extreme
September Weather	18°C (65°F)	456 mm (18.0 inches)	84%	extreme
October Weather	18°C (65°F)	463 mm (18.2 inches)	85%	extreme
November Weather	18°C (65°F)	569 mm (22.4 inches)	83%	extreme
December Weather	19°C (66°F)	559 mm (22.0 inches)	81%	extreme