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September Weather in Hachijo, Japan

Last updated: August 23, 2025

In September, the average temperature in Hachijo, Japan hovers around 27°C (80°F). Expect pleasant warmth with minimums dipping to 22°C (73°F) and maximums reaching 30°C (86°F). However, be prepared for some rain, as the area experiences about 311 mm (12.3 in) of precipitation over 19 days. With an average humidity level of 82%, the air can feel quite moist, making it essential to stay hydrated and comfortable.

September Temperature in Hachijo

In September in Hachijo, the average temperature is 27°C (80°F). Maximum can reach 30°C (86°F) and minimum can be as low as 22°C (73°F). This pleasant climate makes it an ideal destination for travelers seeking warmth and outdoor activities.

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

The chart illustrates September temperature patterns in Hachijo, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Hachijo, September typically has an average temperature of 27°C (80°F), with highs reaching up to 30°C (86°F) and lows dropping to around 22°C (73°F).
JanFebMarAprMayJunJulAugSepOctNovDec565560647074808280746861
Data source: Temperature data for Hachijo 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 Hachijo

In Hachijo in September, the total precipitation amount is 311 mm (12.3 in), recorded over a span of 19 days.

September Precipitation Trends in Hachijo

The chart displays monthly precipitation patterns in Hachijo, 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 Hachijo, September typically receives around 311 mm (12.3 inches) of precipitation spread over approximately 19 days.
JanFebMarAprMayJunJulAugSepOctNovDec13111420113318433817083311334154133
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Hachijo

In Hachijo in September, humidity is 82%. With an average temperature of 27°C (80°F), this humidity feels like a warm blanket enveloping you, making outdoor activities feel sticky and heavy, often leaving travelers longing for shade and a refreshing drink.

September Average Humidity in Hachijo

This chart illustrates the average monthly humidity levels in Hachijo, 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 Hachijo is approximately 82%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec69%68%69%75%82%88%92%85%82%78%74%72%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Hachijo

In Hachijo 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 Hachijo.

Maximum UV Index Levels in Hachijo for September

The chart shows the monthly maximum UV Index (UVI) for Hachijo 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 Hachijo typically reaches 10, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec469111112121110764
Data source: Hachijo 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 Hachijo Compares to Other Months

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

This table compares monthly weather conditions in Hachijo, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather13°C (56°F)130 mm (5.1 inches)69%moderate
February Weather13°C (56°F)114 mm (4.5 inches)68%high
March Weather15°C (60°F)201 mm (7.9 inches)69%very high
April Weather18°C (64°F)133 mm (5.2 inches)75%extreme
May Weather21°C (70°F)184 mm (7.3 inches)82%extreme
June Weather23°C (74°F)338 mm (13.3 inches)88%extreme
July Weather26°C (80°F)170 mm (6.7 inches)92%extreme
August Weather28°C (82°F)83 mm (3.3 inches)85%extreme
September Weather27°C (80°F)311 mm (12.3 inches)82%very high
October Weather24°C (75°F)334 mm (13.1 inches)78%high
November Weather20°C (68°F)154 mm (6.1 inches)74%high
December Weather16°C (61°F)133 mm (5.2 inches)72%moderate

Compare Hachijo's Climate with Cities Worldwide