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September Weather in Nagaoka, Japan

Last updated: August 23, 2025

In September, the average temperature in Nagaoka, Japan is a pleasant 23°C (73°F), making it ideal for outdoor activities. Be prepared for a range, as temperatures can dip to a cool 12°C (54°F) or soar to a sweltering 38°C (100°F). Expect 151 mm (5.9 in) of precipitation spread over 16 days, contributing to an average humidity level of 89%. Prepare for the warmth, but don’t forget your umbrella!

September Temperature in Nagaoka

In September in Nagaoka, the average temperature is 23°C (73°F). The maximum can reach 38°C (100°F), while the minimum can be as low as 12°C (54°F). Travelers should be prepared for warm days and cooler evenings, making it a great time for outdoor adventures and leisurely strolls.

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

The chart illustrates September temperature patterns in Nagaoka, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Nagaoka, September typically has an average temperature of 23°C (73°F), with highs reaching up to 38°C (100°F) and lows dropping to around 12°C (54°F).
JanFebMarAprMayJunJulAugSepOctNovDec363745536471798173625141
Data source: Temperature data for Nagaoka 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 Nagaoka

In Nagaoka in September, the precipitation amount is 151 mm (5.9 in) over a span of 16 days.

September Precipitation Trends in Nagaoka

The chart displays monthly precipitation patterns in Nagaoka, 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 Nagaoka, September typically receives around 151 mm (5.9 inches) of precipitation spread over approximately 16 days.
JanFebMarAprMayJunJulAugSepOctNovDec165138130114110108283186151158139204
Data source: Precipitation data for September generated using information from the Copernicus Climate Change Service.
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September Humidity in Nagaoka

In Nagaoka in September, humidity is 89%. With an average temperature of 23°C (73°F), this humidity feels like a thick, warm blanket wrapping around you, making travel feel sticky and heavy, which can be quite draining for explorers.

September Average Humidity in Nagaoka

This chart illustrates the average monthly humidity levels in Nagaoka, 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 Nagaoka is approximately 89%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec88%87%81%79%81%88%92%92%89%87%85%86%
Data source: Humidity data for September generated using information from the Copernicus Climate Change Service.

September UV Index in Nagaoka

In Nagaoka 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 Nagaoka.

Maximum UV Index Levels in Nagaoka for September

The chart shows the monthly maximum UV Index (UVI) for Nagaoka 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 Nagaoka typically reaches 9, which falls under the very high exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec3479101011119643
Data source: Nagaoka 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 Nagaoka Compares to Other Months

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

This table compares monthly weather conditions in Nagaoka, showing how September’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather2°C (37°F)165 mm (6.5 inches)88%moderate
February Weather3°C (38°F)138 mm (5.4 inches)86%moderate
March Weather7°C (45°F)130 mm (5.1 inches)81%high
April Weather12°C (53°F)114 mm (4.5 inches)78%very high
May Weather18°C (64°F)110 mm (4.3 inches)81%very high
June Weather21°C (71°F)108 mm (4.3 inches)88%very high
July Weather26°C (79°F)283 mm (11.2 inches)92%extreme
August Weather27°C (82°F)186 mm (7.3 inches)92%extreme
September Weather23°C (73°F)151 mm (5.9 inches)89%very high
October Weather17°C (63°F)158 mm (6.2 inches)87%high
November Weather11°C (52°F)139 mm (5.5 inches)85%moderate
December Weather5°C (41°F)204 mm (8.0 inches)86%moderate

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