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December Weather in Kosai, Japan

Last updated: August 23, 2025

In Kosai, Japan, the average temperature in December hovers around a cool 9°C (48°F). Expect a chilly minimum of -1°C (31°F) and a pleasant maximum of 22°C (73°F). During this month, you can anticipate 65 mm (2.6 in) of precipitation spread over 6 days, coupled with an average humidity of 83%. Stay prepared and enjoy the unique climate!

December Temperature in Kosai

In December in Kosai, the average temperature is 9°C (48°F). Maximums can reach 22°C (73°F) and minimums can be as low as -1°C (31°F). Be prepared for a mix of mild days and chilly nights while traveling during this time.

December Weather in Kosai: Daily Temperature Highs, Lows, and Averages

The chart illustrates December temperature patterns in Kosai, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Kosai, December typically has an average temperature of 9°C (48°F), with highs reaching up to 22°C (73°F) and lows dropping to around -1°C (31°F).
JanFebMarAprMayJunJulAugSepOctNovDec444553606874818477685848
Data source: Temperature data for Kosai 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.

December Precipitation in Kosai

In Kosai, in December, the precipitation amount is 65 mm (2.6 in) over a period of 6 days.

December Precipitation Trends in Kosai

The chart displays monthly precipitation patterns in Kosai, with values for each month alongside December’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how December’s conditions compare to those of other months. In Kosai, December typically receives around 65 mm (2.6 inches) of precipitation spread over approximately 6 days.
JanFebMarAprMayJunJulAugSepOctNovDec49691541601872403851892172847565
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Kosai

In Kosai in December humidity is 83%. With an average temperature of 9°C (48°F), this humidity feels like an enveloping blanket, making outdoor activities quite uncomfortable and encouraging travelers to seek shelter or shade frequently.

December Average Humidity in Kosai

This chart illustrates the average monthly humidity levels in Kosai, with December’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In December, average humidity in Kosai is approximately 83%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec82%79%74%76%83%87%93%91%87%85%83%83%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Kosai

In Kosai in December, the maximum UV index reaches 4, which corresponds to a moderate Exposure Category. With a time to burn of 30 minutes, it’s important to take precautions to protect your skin. You can find more details in the Hourly UV Index in Kosai for better planning.

Maximum UV Index Levels in Kosai for December

The chart shows the monthly maximum UV Index (UVI) for Kosai in December, 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 December, the maximum UV index in Kosai typically reaches 4, which falls under the moderate exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec458101111121110754
Data source: Kosai December 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 December Weather in Kosai Compares to Other Months

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

This table compares monthly weather conditions in Kosai, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather6°C (44°F)49 mm (1.9 inches)82%moderate
February Weather7°C (45°F)69 mm (2.7 inches)79%moderate
March Weather12°C (53°F)154 mm (6.1 inches)74%very high
April Weather16°C (60°F)160 mm (6.3 inches)76%very high
May Weather20°C (69°F)187 mm (7.4 inches)83%extreme
June Weather23°C (74°F)240 mm (9.4 inches)87%extreme
July Weather27°C (81°F)385 mm (15.2 inches)93%extreme
August Weather29°C (85°F)189 mm (7.4 inches)91%extreme
September Weather25°C (78°F)217 mm (8.5 inches)87%very high
October Weather20°C (68°F)284 mm (11.2 inches)85%high
November Weather14°C (58°F)75 mm (2.9 inches)83%moderate
December Weather9°C (48°F)65 mm (2.6 inches)83%moderate

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