September Weather in Isawa, Japan

Last updated: August 23, 2025

The average temperature in Isawa, Japan during September is a pleasant 18°C (65°F). Expect a minimum of 9°C (49°F) and a maximum of 31°C (87°F). Alongside this comfortable climate, anticipate precipitation totaling 208 mm (8.2 in) over approximately 22 days, with an average humidity of 86%.

September Temperature in Isawa

In September in Isawa, the average temperature is 18°C (65°F). Maximums can reach 31°C (87°F), and minimums can drop as low as 9°C (49°F). This makes Isawa a comfortable destination for travelers looking to enjoy mild weather while exploring the area.

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

The chart illustrates September temperature patterns in Isawa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Isawa, September typically has an average temperature of 18°C (65°F), with highs reaching up to 31°C (87°F) and lows dropping to around 9°C (49°F).

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

September Precipitation in Isawa

In Isawa in September, the precipitation amount is 208 mm (8.2 in) over a span of 22 days.

September Precipitation Trends in Isawa

The chart displays monthly precipitation patterns in Isawa, 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 Isawa, September typically receives around 208 mm (8.2 inches) of precipitation spread over approximately 22 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 Isawa

In Isawa in September humidity is 86%. With an average temperature of 18°C (65°F), this humidity feels like you’re wrapped in a warm, heavy blanket, making outdoor activities feel quite muggy and sticky for traveling.

September Average Humidity in Isawa

This chart illustrates the average monthly humidity levels in Isawa, 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 Isawa is approximately 86%, 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 Isawa

In Isawa 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 Isawa.

Maximum UV Index Levels in Isawa for September

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

Data source: Isawa 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 Isawa Compares to Other Months

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

This table compares monthly weather conditions in Isawa, 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 (31°F)	48 mm (1.9 inches)	76%	moderate
February Weather	0°C (33°F)	58 mm (2.3 inches)	74%	high
March Weather	5°C (41°F)	144 mm (5.7 inches)	70%	very high
April Weather	9°C (48°F)	138 mm (5.4 inches)	74%	very high
May Weather	14°C (58°F)	148 mm (5.8 inches)	81%	extreme
June Weather	17°C (63°F)	179 mm (7.1 inches)	88%	extreme
July Weather	21°C (70°F)	320 mm (12.6 inches)	93%	extreme
August Weather	23°C (73°F)	190 mm (7.5 inches)	90%	extreme
September Weather	18°C (65°F)	208 mm (8.2 inches)	86%	very high
October Weather	13°C (55°F)	324 mm (12.8 inches)	83%	high
November Weather	7°C (45°F)	56 mm (2.2 inches)	80%	moderate
December Weather	2°C (36°F)	52 mm (2.1 inches)	78%	moderate