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September Weather in Iruma, Japan

Last updated: August 23, 2025

In Iruma, Japan, the average temperature in September is a pleasant 22°C (71°F). However, temperatures can vary significantly, with a minimum of 12°C (53°F) and a maximum reaching up to 35°C (94°F). Expect around 247 mm (9.7 in) of precipitation spread across 22 days, contributing to an average humidity level of 86%. Whether you're enjoying the warmth or navigating the rain, September in Iruma offers a dynamic climate experience!

September Temperature in Iruma

In September in Iruma, the average temperature is 22°C (71°F), with maximums reaching 35°C (94°F) and minimums dropping as low as 12°C (53°F). This diverse temperature range makes Iruma an ideal destination for travelers looking for comfortable days and cooler evenings.

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

The chart illustrates September temperature patterns in Iruma, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Iruma, September typically has an average temperature of 22°C (71°F), with highs reaching up to 35°C (94°F) and lows dropping to around 12°C (53°F).
JanFebMarAprMayJunJulAugSepOctNovDec373946546368757971615242
Data source: Temperature data for Iruma generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

September Precipitation in Iruma

In Iruma in September, the total precipitation amount is 247 mm (9.7 in) over a period of 22 days.

September Precipitation Trends in Iruma

The chart displays monthly precipitation patterns in Iruma, 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 Iruma, September typically receives around 247 mm (9.7 inches) of precipitation spread over approximately 22 days.
JanFebMarAprMayJunJulAugSepOctNovDec53621661501482093121952473467262
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Iruma

In Iruma in September humidity is 86%. With an average temperature of 22°C (71°F), this humidity feels like a heavy blanket wrapping around you, making outdoor activities feel muggy and draining.

September Average Humidity in Iruma

This chart illustrates the average monthly humidity levels in Iruma, 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 Iruma is approximately 86%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec76%74%70%74%82%88%93%90%86%83%80%78%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Iruma

In Iruma 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 Iruma.

Maximum UV Index Levels in Iruma for September

The chart shows the monthly maximum UV Index (UVI) for Iruma 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 Iruma typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46891111111110754
Data source: Iruma 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 Iruma Compares to Other Months

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

This table compares monthly weather conditions in Iruma, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather3°C (37°F)53 mm (2.1 inches)76%moderate
February Weather4°C (40°F)62 mm (2.4 inches)74%high
March Weather8°C (47°F)166 mm (6.5 inches)70%very high
April Weather12°C (54°F)150 mm (5.9 inches)74%very high
May Weather17°C (64°F)148 mm (5.8 inches)81%extreme
June Weather20°C (69°F)209 mm (8.2 inches)88%extreme
July Weather24°C (76°F)312 mm (12.3 inches)93%extreme
August Weather26°C (79°F)195 mm (7.7 inches)90%extreme
September Weather22°C (71°F)247 mm (9.7 inches)86%very high
October Weather16°C (61°F)346 mm (13.6 inches)83%high
November Weather11°C (52°F)72 mm (2.8 inches)80%moderate
December Weather5°C (42°F)62 mm (2.4 inches)78%moderate

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