September Weather in Koga, Japan

Last updated: August 23, 2025

In September, the average temperature in Koga, Japan is a pleasant 23°C (74°F), with lows dipping to a cool 13°C (55°F) and highs reaching a warm 35°C (95°F). Travelers should prepare for some rain, as the region sees about 195 mm (7.7 in) of precipitation over 20 days. With an average humidity of 89%, it’s advisable to stay hydrated and enjoy the lush surroundings!

September Temperature in Koga

In September in Koga, the average temperature is 23°C (74°F). Maximum can reach 35°C (95°F) and minimum can be as low as 13°C (55°F). This pleasant climate makes Koga an ideal destination for travelers looking to enjoy outdoor activities and explore the local attractions.

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

The chart illustrates September temperature patterns in Koga, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Koga, September typically has an average temperature of 23°C (74°F), with highs reaching up to 35°C (95°F) and lows dropping to around 13°C (55°F).

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

September Precipitation in Koga

In Koga in September, the precipitation amount is 195 mm (7.7 in) spread over 20 days.

September Precipitation Trends in Koga

The chart displays monthly precipitation patterns in Koga, 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 Koga, September typically receives around 195 mm (7.7 inches) of precipitation spread over approximately 20 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 Koga

In Koga in September humidity is 89%. With an average temperature of 23°C (74°F), this humidity feels like a warm, heavy blanket enveloping you, making traveling feel stifling and exhausting as you navigate the thick air.

September Average Humidity in Koga

This chart illustrates the average monthly humidity levels in Koga, 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 Koga is approximately 89%, 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 Koga

In Koga in September, the maximum UV index is 9, which corresponds to a very high Exposure Category. The time to burn is just 15 minutes, so it's essential to take precautions. For detailed information, you can check the Hourly UV Index in Koga.

Maximum UV Index Levels in Koga for September

The chart shows the monthly maximum UV Index (UVI) for Koga 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 Koga typically reaches 9, which falls under the very high exposure category.

Data source: Koga 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 Koga Compares to Other Months

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

This table compares monthly weather conditions in Koga, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	4°C (39°F)	38 mm (1.5 inches)	88%	moderate
February Weather	5°C (41°F)	41 mm (1.6 inches)	86%	moderate
March Weather	9°C (49°F)	131 mm (5.2 inches)	81%	high
April Weather	14°C (57°F)	129 mm (5.1 inches)	78%	very high
May Weather	19°C (66°F)	137 mm (5.4 inches)	81%	very high
June Weather	22°C (72°F)	160 mm (6.3 inches)	88%	extreme
July Weather	26°C (78°F)	258 mm (10.2 inches)	92%	extreme
August Weather	27°C (82°F)	156 mm (6.1 inches)	92%	very high
September Weather	23°C (74°F)	195 mm (7.7 inches)	89%	very high
October Weather	18°C (64°F)	258 mm (10.1 inches)	87%	high
November Weather	12°C (53°F)	67 mm (2.6 inches)	85%	moderate
December Weather	6°C (43°F)	50 mm (2.0 inches)	86%	moderate