September Weather in Yonezawa, Japan

Last updated: August 23, 2025

In September, the average temperature in Yonezawa, Japan is a pleasant 19°C (66°F). This month can see temperatures ranging from a brisk 7°C (45°F) to a warm 31°C (89°F). Expect 140 mm (5.5 in) of precipitation spread over about 15 days, contributing to the region's average humidity of 89%. Perfect for those who enjoy a lush, green atmosphere!

September Temperature in Yonezawa

In September in Yonezawa, the average temperature is 19°C (66°F). The maximum can reach 31°C (89°F), and the minimum can be as low as 7°C (45°F). This makes it an ideal time for travelers to enjoy a mix of warm days and cooler evenings, perfect for exploring and outdoor activities.

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

The chart illustrates September temperature patterns in Yonezawa, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Yonezawa, September typically has an average temperature of 19°C (66°F), with highs reaching up to 31°C (89°F) and lows dropping to around 7°C (45°F).

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

September Precipitation in Yonezawa

In Yonezawa in September, the total precipitation amount is 140 mm (5.5 in) over a span of 15 days.

September Precipitation Trends in Yonezawa

The chart displays monthly precipitation patterns in Yonezawa, 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 Yonezawa, September typically receives around 140 mm (5.5 inches) of precipitation spread over approximately 15 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 Yonezawa

In Yonezawa in September humidity is 89%. With an average temperature of 19°C (66°F), this humidity feels like walking through a damp blanket, making every step more laborious and the air thick, potentially leading to discomfort while exploring or sightseeing.

September Average Humidity in Yonezawa

This chart illustrates the average monthly humidity levels in Yonezawa, 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 Yonezawa 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 Yonezawa

In Yonezawa 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 Yonezawa.

Maximum UV Index Levels in Yonezawa for September

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

Data source: Yonezawa 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 Yonezawa Compares to Other Months

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

This table compares monthly weather conditions in Yonezawa, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-2°C (28°F)	169 mm (6.6 inches)	88%	moderate
February Weather	-2°C (29°F)	167 mm (6.6 inches)	86%	moderate
March Weather	2°C (36°F)	153 mm (6.0 inches)	81%	very high
April Weather	8°C (46°F)	138 mm (5.4 inches)	78%	very high
May Weather	14°C (58°F)	120 mm (4.7 inches)	81%	very high
June Weather	18°C (64°F)	135 mm (5.3 inches)	88%	extreme
July Weather	22°C (72°F)	298 mm (11.7 inches)	92%	extreme
August Weather	23°C (74°F)	221 mm (8.7 inches)	92%	extreme
September Weather	19°C (66°F)	140 mm (5.5 inches)	89%	very high
October Weather	13°C (55°F)	164 mm (6.5 inches)	87%	high
November Weather	7°C (44°F)	118 mm (4.7 inches)	85%	moderate
December Weather	0°C (33°F)	203 mm (8.0 inches)	86%	moderate