Contents
- Weather in December
- Frequently asked questions
- Average temperature in December
- Average pressure in December
- Average wind speed in December
- Average humidity in December
- Average rainfall in December
- Average rainfall days in December
- Average snowfall in December
- Average snowfall days in December
- Average daylight in December
- Average sunshine in December
- Average sunshine days in December
- Average UV index in December
- Average cloud cover in December
- Average visibility in December
December
Weather in December
Temperature
A decrease in the average high-temperature is observed during December, shifting from an icy 4.9°C (40.8°F) in November to a subzero cold -1.6°C (29.1°F). Iwanai, during the December nights, maintains an average temperature of -6°C (21.2°F), closely aligned with its daytime readings.Humidity
The average relative humidity in December is 88%.Rainfall
In Iwanai, during December, the rain falls for 6.5 days and regularly aggregates up to 102mm (4.02") of precipitation. In Iwanai, during the entire year, the rain falls for 157.1 days and collects up to 887mm (34.92") of precipitation.Snowfall
January through May, October through December are months with snowfall. The month with the most snowfall is December, when snow falls for 25.9 days and typically aggregates up to 598mm (23.54") of snow.Daylight
With an average of 9h and 6min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 06:49 and sunset at 16:04. On the last day of December, sunrise is at 07:08 and sunset at 16:12 JST.
Sunshine
The average sunshine in December is 1.7h.UV index
January through March, November and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for the average person.Note: A maximum UV index of 1 in December translates into the following recommendations:
While sun exposure does not greatly affect most, individuals with fair skin, babies, and children always need vigilant safeguarding. Avoid the Sun's strongest UV rays by seeking shade and limiting exposure during midday. Wearing sunglasses with both UVA and UVB protection effectively reduces sun-induced eye damage. Remember to consider! The UV radiation from the Sun can be intensified nearly twice by the reflection of snow.
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What is the average humidity in December?
How many days does it rain in December?
What is the snowiest month?
How much does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December in Iwanai?
What time are sunrise and sunset in December?
How many hours of sunshine does Iwanai have in December?
What is the month with the lowest UV index?
How high is the UV index in December?
Average temperature in December
Iwanai, Japan
- Average high temperature in December: -1.6°C
The warmest month (with the highest average high temperature) is August (23.3°C).
The month with the lowest average high temperature is January (-3.8°C).
- Average low temperature in December: -6°C
The month with the highest average low temperature is August (16.1°C).
The coldest month (with the lowest average low temperature) is February (-8.9°C).
Average pressure in December
Iwanai, Japan
- Average pressure in December: 1013.4mbar
The month with the highest atmospheric pressure is November (1016.4mbar).
The month with the lowest atmospheric pressure is July (1008.4mbar).
Average wind speed in December
Iwanai, Japan
- Average wind speed in December: 14.5km/h
The windiest month (with the highest average wind speed) is December (14.5km/h).
The calmest month (with the lowest average wind speed) is August (8km/h).
Average humidity in December
Iwanai, Japan
- Average humidity in December: 88%
The months with the highest relative humidity are January and February (89%).
The month with the lowest relative humidity is April (79%).
Average rainfall in December
Iwanai, Japan
- Average rainfall in December: 102mm
The wettest month (with the highest rainfall) is August (105mm).
The driest month (with the least rainfall) is April (52mm).
Average rainfall days in December
Iwanai, Japan
- Average rainfall days in December: 6.5 days
The month with the highest number of rainy days is August (19.1 days).
The month with the least rainy days is January (3.4 days).
Average snowfall in December
Iwanai, Japan
- Average snowfall in December: 598mm
The month with the highest snowfall is December (598mm).
The months with the least snowfall are June, July, August and September (0mm).
Average snowfall days in December
Iwanai, Japan
- Average snowfall days in December: 25.9 days
The month with the highest number of snowfall days is January (28.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Iwanai, Japan
- Average daylight in December: 9h and 1min
The month with the longest days is June (Average daylight: 15h and 18min).
The month with the shortest days is December (Average daylight: 9h and 6min).
- Average sunshine in December: 1h and 4min
The months with the most sunshine are May and August (Average sunshine: 8h and 24min).
The month with the least sunshine is January (Average sunshine: 1h and 24min).
Average sunshine days in December
Iwanai, Japan
- Average sunshine days in December: 3.1 days
The month with the most sunshine days is May (13.3 days).
The month with the least sunshine days is January (2.7 days).
Average UV index in December
Iwanai, Japan
- Average UV index in December: 1
The months with the highest UV index are July and August (UV index 5).
The months with the lowest UV index are January, February, March, November and December (UV index 1).
Average cloud cover in December
Iwanai, Japan
- Average cloud cover in December: 83
The month with the most cloud cover is January (Cloud cover 86).
The month with the least cloud cover is September (Cloud cover 43).
Average visibility in December
Iwanai, Japan
- Average visibility in December: 7km
The months with the highest visibility are April, May and October (9km).
The months with the lowest visibility are January, February, July, August and December (7km).
