December weather forecastKoyasu, Japan

December

Weather in December

December, the first month of the winter in Koyasu, is still a cool month, with an average temperature varying between 12.5°C (54.5°F) and 8.4°C (47.1°F).

Temperature

A minor decrease in the average high-temperature is observed during December, shifting from a comfortable 17.1°C (62.8°F) in November to a cool 12.5°C (54.5°F). During the month of December, Koyasu's average nighttime temperature closely mirrors its daytime counterpart, at a frosty 8.4°C (47.1°F).

Humidity

The average relative humidity in December is 64%.

Rainfall

February and December are months with the least rain in Koyasu when the rain falls for 8.7 days and typically aggregates up to 39mm (1.54") of rain.

Snowfall

In Koyasu, Japan, snow does not fall in April through December.

Daylight

With an average of 9h and 48min of daylight, December has the shortest days of the year.
On the first day of December in Koyasu, sunrise is at 06:33 and sunset at 16:30. On the last day of the month, sunrise is at 06:51 and sunset at 16:40 JST.

Sunshine

The average sunshine in December in Koyasu is 6.1h.

UV index

The months with the lowest UV index are January, February and December, with an average maximum UV index of 3. A UV Index of 3 to 5 symbolizes a moderate health risk from exposure to the Sun's UV rays for average individuals.
Note: In December, the maximum UV index of 3 translates into these guidelines:
Prioritize safety - The need to safeguard skin and eyes from harm is emphasized. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. To cut down UV radiation exposure by about half, sport a wide-brim hat.

Updated: Jan 31, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

In Koyasu, 12.5°C (54.5°F) is the average high-temperature and 8.4°C (47.1°F) is the average low-temperature during December. In August, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which combines air temperature and relative humidity, is computed to be 34°C (93.2°F).

In December, the average relative humidity in Koyasu is 64%.

February and December are months with the least rain in Koyasu when the rain falls for 8.7 days and typically aggregates up to 39mm (1.54") of rain.

In December, in Koyasu, the rain falls for 8.7 days. Throughout December, 39mm (1.54") of precipitation is accumulated.

In Koyasu, Japan, snow does not fall in April through December.

In Koyasu, in December, it doesn't snow. In January, it regularly snows.

The month with the shortest days in Koyasu, Japan, is December, with an average of 9h and 48min of daylight.

In Koyasu, Japan, the average day length in December is 9h and 49min.

In December, on the first day of the month, sunrise is at 06:33 and sunset at 16:30. On the last day of the month, in Koyasu, sunrise is at 06:51 and sunset at 16:40 JST.

In December, the average sunshine duration in Koyasu is 6.1h.

The months with the lowest UV index are January, February and December, with an average maximum UV index of 3.

The average daily maximum UV index in December is 3. A UV Index value of 3 to 5 symbolizes a medium hazard to health from exposure to Sun's UV rays.

Today

Tomorrow

Long-term

Year J F M A M J J A S O N December

Nov

December

Jan

Average high temperature

17.1°C

12.5°C

9.8°C

Average low temperature

Average pressure

Average wind speed

Average max. wind speed

19.3km/h

21.2km/h

20.9km/h

Average wind speed gusts

Average humidity

Average rainfall

Average rainfall days

Average snowfall

Average snowfall days

Average daylight

Average sunshine

Average sunshine days

15.2

21.3

23.2

Average UV index

Average cloud cover

Average visibility

Average temperature in December
Koyasu, Japan

Average high temperature in December: 12.5°C

The warmest month (with the highest average high temperature) is August (28.8°C).
The month with the lowest average high temperature is January (9.8°C).

Average low temperature in December: 8.4°C

The month with the highest average low temperature is August (25.3°C).
The coldest month (with the lowest average low temperature) is January (5.3°C).

Average pressure in December
Koyasu, Japan

Average pressure in December: 1016.2mbar

The month with the highest atmospheric pressure is November (1017.9mbar).
The month with the lowest atmospheric pressure is June (1009.1mbar).

Average wind speed in December
Koyasu, Japan

Average wind speed in December: 19.1km/h

The windiest month (with the highest average wind speed) is March (20.8km/h).
The calmest month (with the lowest average wind speed) is June (15.9km/h).

Average humidity in December
Koyasu, Japan

Average humidity in December: 64%

The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is January (61%).

Average rainfall in December
Koyasu, Japan

Average rainfall in December: 39mm

The wettest month (with the highest rainfall) is September (125mm).
The driest months (with the least rainfall) are February and December (39mm).

Average rainfall days in December
Koyasu, Japan

Average rainfall days in December: 8.7 days

The month with the highest number of rainy days is June (16.5 days).
The month with the least rainy days is January (6.5 days).

Average snowfall in December
Koyasu, Japan

Average snowfall in December: 0mm

The month with the highest snowfall is February (10mm).
The months with the least snowfall are April, May, June, July, August, September, October, November and December (0mm).

Average snowfall days in December
Koyasu, Japan

Average snowfall days in December: 0 days

The month with the highest number of snowfall days is February (0.5 days).
The months with the least snowfall days are April, May, June, July, August, September, October, November and December (0 days).

Average daylight in December /
Average sunshine in December
Koyasu, Japan

Average daylight in December: 9h and 48min

The month with the longest days is June (Average daylight: 14h and 30min).
The month with the shortest days is December (Average daylight: 9h and 48min).

Average sunshine in December: 6h and 6min

The month with the most sunshine is August (Average sunshine: 10h and 42min).
The month with the least sunshine is February (Average sunshine: 5h and 30min).

Average sunshine days in December
Koyasu, Japan

Average sunshine days in December: 21.3 days

The month with the most sunshine days is January (23.2 days).
The month with the least sunshine days is September (11.2 days).

Average UV index in December
Koyasu, Japan

Average UV index in December: 3

The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January, February and December (UV index 3).

Average cloud cover in December
Koyasu, Japan

Average cloud cover in December: 31

The months with the most cloud cover are March, June and October (Cloud cover 43).
The month with the least cloud cover is August (Cloud cover 29).

Average visibility in December
Koyasu, Japan

Average visibility in December: 10km

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (10km).