September Weather in Koa, Indonesia

Last updated: August 23, 2025

In September, the average temperature in Koa, Indonesia reaches a comfortable 26°C (80°F). Expect pleasant days with highs of 35°C (96°F) and cool evenings that can drop to 16°C (61°F). You'll want to stay hydrated, as the average humidity hovers around 74%. With just 9 mm (0.3 in) of precipitation spread over 2 days, there's plenty of sunshine to enjoy!

September Temperature in Koa

In September in Koa, the average temperature is 26°C (80°F). Maximums can reach 35°C (96°F), and minimums can be as low as 16°C (61°F). This pleasant climate makes it an ideal time for outdoor activities and exploring the local attractions.

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

The chart illustrates September temperature patterns in Koa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Koa, September typically has an average temperature of 26°C (80°F), with highs reaching up to 35°C (96°F) and lows dropping to around 16°C (61°F).

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

September Precipitation in Koa

In Koa in September, the precipitation amount is 9 mm (0.3 in) over a period of 2 days.

September Precipitation Trends in Koa

The chart displays monthly precipitation patterns in Koa, 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 Koa, September typically receives around 9 mm (0.3 inches) of precipitation spread over approximately 2 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 Koa

In Koa in September humidity is 74%. With an average temperature of 26°C (80°F), this humidity feels like a warm, thick blanket wrapping around you, making any outdoor activities feel more strenuous and sweat-inducing, so staying hydrated and taking frequent breaks in the shade is essential for enjoyable traveling.

September Average Humidity in Koa

This chart illustrates the average monthly humidity levels in Koa, 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 Koa is approximately 74%, 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 Koa

In Koa 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 Koa.

Maximum UV Index Levels in Koa for September

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

Data source: Koa 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 Koa Compares to Other Months

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

This table compares monthly weather conditions in Koa, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	26°C (79°F)	202 mm (8.0 inches)	77%	extreme
February Weather	26°C (79°F)	150 mm (5.9 inches)	82%	extreme
March Weather	26°C (79°F)	178 mm (7.0 inches)	82%	extreme
April Weather	26°C (79°F)	129 mm (5.1 inches)	80%	extreme
May Weather	26°C (79°F)	40 mm (1.6 inches)	80%	extreme
June Weather	26°C (78°F)	10 mm (0.4 inches)	75%	very high
July Weather	25°C (77°F)	8 mm (0.3 inches)	71%	extreme
August Weather	25°C (78°F)	5 mm (0.2 inches)	74%	extreme
September Weather	26°C (80°F)	9 mm (0.3 inches)	74%	extreme
October Weather	27°C (81°F)	43 mm (1.7 inches)	74%	extreme
November Weather	27°C (81°F)	147 mm (5.8 inches)	73%	extreme
December Weather	27°C (80°F)	209 mm (8.2 inches)	72%	extreme