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December Weather in Sai, Japan

Last updated: August 23, 2025

In Sai, Japan, the month of December experiences an average temperature of 3°C (38°F). Temperatures can dip to a brisk -5°C (24°F) and can rise to a mild 15°C (59°F). During this time, precipitation averages 167 mm (6.6 in) over 26 days, contributing to an overall average humidity of 77%.

December Temperature in Sai

In December in Sai, the average temperature is 3°C (38°F), with maximums reaching up to 15°C (59°F) and minimums plummeting as low as -5°C (24°F). It's essential to pack layers and prepare for chilly conditions if you're planning to travel during this time.

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

The chart illustrates December temperature patterns in Sai, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Sai, December typically has an average temperature of 3°C (38°F), with highs reaching up to 15°C (59°F) and lows dropping to around -5°C (24°F).
JanFebMarAprMayJunJulAugSepOctNovDec343340465259677269614938
Data source: Temperature data for Sai 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 Sai

In Sai in December, the total precipitation amount reaches 167 mm (6.6 in) over the course of 26 days.

December Precipitation Trends in Sai

The chart displays monthly precipitation patterns in Sai, 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 Sai, December typically receives around 167 mm (6.6 inches) of precipitation spread over approximately 26 days.
JanFebMarAprMayJunJulAugSepOctNovDec1121179398104112110188132156131168
Data source: Precipitation data for December generated using information from the Copernicus Climate Change Service.
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December Humidity in Sai

In Sai in December humidity is 77%. With an average temperature of 3°C (38°F), this humidity feels like a damp chill enveloping you, making any outdoor adventure feel more intense as you navigate the biting cold mixed with the heavy air.

December Average Humidity in Sai

This chart illustrates the average monthly humidity levels in Sai, 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 Sai is approximately 77%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec79%78%77%78%86%91%95%97%89%82%78%77%
Data source: Humidity data for December generated using information from the Copernicus Climate Change Service.

December UV Index in Sai

In Sai in December, the maximum UV index is 2, which corresponds to a low exposure category. With this level of UV radiation, the time to burn is approximately 45 minutes. To learn more about the hourly UV index in Sai, you can visit Hourly UV Index in Sai.

Maximum UV Index Levels in Sai for December

The chart shows the monthly maximum UV Index (UVI) for Sai 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 Sai typically reaches 2, which falls under the low exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec235891010118632
Data source: Sai 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 Sai Compares to Other Months

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

This table compares monthly weather conditions in Sai, showing how December’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather1°C (34°F)112 mm (4.4 inches)79%low
February Weather1°C (34°F)117 mm (4.6 inches)78%moderate
March Weather4°C (40°F)93 mm (3.7 inches)77%moderate
April Weather8°C (46°F)98 mm (3.9 inches)78%very high
May Weather11°C (53°F)103 mm (4.1 inches)86%very high
June Weather15°C (59°F)112 mm (4.4 inches)91%very high
July Weather19°C (67°F)110 mm (4.3 inches)95%very high
August Weather22°C (72°F)187 mm (7.4 inches)97%extreme
September Weather21°C (69°F)132 mm (5.2 inches)89%very high
October Weather16°C (61°F)156 mm (6.1 inches)81%high
November Weather9°C (49°F)131 mm (5.1 inches)78%moderate
December Weather3°C (38°F)167 mm (6.6 inches)77%low

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