September Weather in Kai, Japan

Last updated: August 23, 2025

In September, the average temperature in Kai, Japan is a comfortable 18°C (65°F). However, be prepared for a temperature range that can dip as low as 8°C (47°F) and soar up to 30°C (86°F). Expect a fair amount of rain, with 183 mm (7.2 in) of precipitation spread over 18 days. Don't forget to account for the humidity, which averages a steamy 86%!

September Temperature in Kai

In September in Kai, the average temperature is 18°C (65°F), with maximums reaching 30°C (86°F) and minimums dropping as low as 8°C (47°F). This pleasant climate makes it an ideal time for travelers to explore the outdoor attractions and enjoy recreational activities.

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

The chart illustrates September temperature patterns in Kai, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Kai, September typically has an average temperature of 18°C (65°F), with highs reaching up to 30°C (86°F) and lows dropping to around 8°C (47°F).

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

September Precipitation in Kai

In Kai in September, the precipitation amount is 183 mm (7.2 in) over the course of 18 days.

September Precipitation Trends in Kai

The chart displays monthly precipitation patterns in Kai, 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 Kai, September typically receives around 183 mm (7.2 inches) of precipitation spread over approximately 18 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 Kai

In Kai 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 Kai

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

In Kai 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 Kai.

Maximum UV Index Levels in Kai for September

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

Data source: Kai 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 Kai Compares to Other Months

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

This table compares monthly weather conditions in Kai, 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)	48 mm (1.9 inches)	76%	moderate
February Weather	0°C (32°F)	60 mm (2.4 inches)	74%	high
March Weather	4°C (40°F)	136 mm (5.4 inches)	70%	very high
April Weather	9°C (48°F)	129 mm (5.1 inches)	74%	very high
May Weather	14°C (58°F)	138 mm (5.4 inches)	81%	extreme
June Weather	17°C (64°F)	147 mm (5.8 inches)	88%	extreme
July Weather	21°C (70°F)	293 mm (11.6 inches)	93%	extreme
August Weather	23°C (73°F)	150 mm (5.9 inches)	90%	extreme
September Weather	18°C (65°F)	183 mm (7.2 inches)	86%	very high
October Weather	13°C (55°F)	277 mm (10.9 inches)	83%	high
November Weather	7°C (45°F)	52 mm (2.0 inches)	80%	high
December Weather	1°C (35°F)	54 mm (2.1 inches)	78%	moderate