September Weather in Katsuyama, Japan

Last updated: August 23, 2025

In September, the average temperature in Katsuyama, Japan is a pleasant 20°C (68°F). Expect a range of temperatures, with minimums dipping to 8°C (46°F) and maximums soaring up to 31°C (88°F). Rainfall isn't uncommon, with an average precipitation of 244 mm (9.6 in) over 16 days. Adding to the atmosphere, the average humidity sits at a muggy 87%.

September Temperature in Katsuyama

In September in Katsuyama, the average temperature is 20°C (68°F). Maximums can reach 31°C (88°F), while minimums can drop as low as 8°C (46°F). This makes it a pleasant time to visit, offering comfortable daytime warmth and cooler evenings for a variety of outdoor activities.

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

The chart illustrates September temperature patterns in Katsuyama, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Katsuyama, September typically has an average temperature of 20°C (68°F), with highs reaching up to 31°C (88°F) and lows dropping to around 8°C (46°F).

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

September Precipitation in Katsuyama

In Katsuyama in September, the precipitation amount is 244 mm (9.6 in) over the course of 16 days.

September Precipitation Trends in Katsuyama

The chart displays monthly precipitation patterns in Katsuyama, 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 Katsuyama, September typically receives around 244 mm (9.6 inches) of precipitation spread over approximately 16 days.

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

Choose your preferred precipitation unit

Millimeters (mm) Inches (in)

September Humidity in Katsuyama

In Katsuyama in September, humidity is 87%. With an average temperature of 20°C (68°F), this humidity feels like a warm, thick blanket enveloping you, making travel feel a bit sluggish and requiring frequent breaks to stay refreshed.

September Average Humidity in Katsuyama

This chart illustrates the average monthly humidity levels in Katsuyama, 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 Katsuyama is approximately 87%, 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 Katsuyama

In Katsuyama in September, the maximum UV index reaches 10, which corresponds to a very high Exposure Category. With a time to burn of just 15 minutes, it's crucial to take precautions. For more detailed information, you can check the Hourly UV Index in Katsuyama.

Maximum UV Index Levels in Katsuyama for September

The chart shows the monthly maximum UV Index (UVI) for Katsuyama 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 Katsuyama typically reaches 10, which falls under the very high exposure category.

Data source: Katsuyama 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 Katsuyama Compares to Other Months

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

This table compares monthly weather conditions in Katsuyama, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-1°C (30°F)	165 mm (6.5 inches)	82%	moderate
February Weather	-1°C (31°F)	167 mm (6.6 inches)	79%	high
March Weather	4°C (40°F)	191 mm (7.5 inches)	74%	very high
April Weather	9°C (49°F)	216 mm (8.5 inches)	76%	very high
May Weather	15°C (59°F)	201 mm (7.9 inches)	83%	extreme
June Weather	18°C (65°F)	226 mm (8.9 inches)	87%	extreme
July Weather	23°C (73°F)	436 mm (17.2 inches)	93%	extreme
August Weather	24°C (76°F)	304 mm (12.0 inches)	91%	extreme
September Weather	20°C (68°F)	244 mm (9.6 inches)	87%	very high
October Weather	14°C (58°F)	230 mm (9.1 inches)	85%	high
November Weather	8°C (46°F)	127 mm (5.0 inches)	83%	moderate
December Weather	2°C (36°F)	195 mm (7.7 inches)	83%	moderate