September Weather in Omachi, Japan

Last updated: August 23, 2025

In Omachi, Japan, the average temperature in September hovers around 16°C (61°F), with a minimum dipping to 2°C (36°F) and a maximum soaring to 27°C (80°F). Prepare for a wet month, as 334 mm (13.1 in) of precipitation falls over approximately 20 days, resulting in an average humidity of a humid 89%.

September Temperature in Omachi

In September, in Omachi, the average temperature is 16°C (61°F). The maximum can reach 27°C (80°F) and the minimum can be as low as 2°C (36°F). This variation makes it a great time for travelers to enjoy a range of outdoor activities while being prepared for cooler evenings.

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

The chart illustrates September temperature patterns in Omachi, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Omachi, September typically has an average temperature of 16°C (61°F), with highs reaching up to 27°C (80°F) and lows dropping to around 2°C (36°F).

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

September Precipitation in Omachi

In Omachi in September, the precipitation amount is 334 mm (13.1 in) over the course of 20 days.

September Precipitation Trends in Omachi

The chart displays monthly precipitation patterns in Omachi, 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 Omachi, September typically receives around 334 mm (13.1 inches) of precipitation spread over approximately 20 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 Omachi

In Omachi in September, humidity is 89%. With an average temperature of 16°C (61°F), this humidity feels like a heavy blanket enveloping you, making outdoor activities feel sluggish and sticky, which can be quite challenging for travelers looking to explore.

September Average Humidity in Omachi

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

In Omachi 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 Omachi.

Maximum UV Index Levels in Omachi for September

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

Data source: Omachi 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 Omachi Compares to Other Months

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

This table compares monthly weather conditions in Omachi, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
	Temperature	Precipitation	Humidity	UV
January Weather	-8°C (19°F)	193 mm (7.6 inches)	88%	moderate
February Weather	-7°C (20°F)	181 mm (7.1 inches)	86%	high
March Weather	-1°C (30°F)	198 mm (7.8 inches)	81%	very high
April Weather	4°C (39°F)	226 mm (8.9 inches)	78%	very high
May Weather	11°C (52°F)	276 mm (10.9 inches)	81%	extreme
June Weather	15°C (59°F)	310 mm (12.2 inches)	88%	extreme
July Weather	19°C (67°F)	565 mm (22.3 inches)	92%	extreme
August Weather	20°C (69°F)	400 mm (15.8 inches)	92%	extreme
September Weather	16°C (61°F)	334 mm (13.1 inches)	89%	very high
October Weather	10°C (50°F)	284 mm (11.2 inches)	87%	high
November Weather	3°C (37°F)	139 mm (5.5 inches)	85%	moderate
December Weather	-5°C (24°F)	206 mm (8.1 inches)	86%	moderate