December weather forecastIyo, Japan

December

Weather in December

December, the first month of the winter in Iyo, is still a chilly month, with temperature in the range of an average low of 5°C (41°F) and an average high of 9.9°C (49.8°F).

Temperature

A change in temperatures is noted as November gives way to December, with average highs reducing from a moderate 15.5°C (59.9°F) to a frosty 9.9°C (49.8°F). Night temperatures during December in Iyo stabilize at an average of 5°C (41°F), closely mirroring the daytime temperatures.

Humidity

The average relative humidity in December in Iyo is 74%.

Rainfall

In Iyo, in December, during 10.7 rainfall days, 38mm (1.5") of precipitation is typically accumulated. In Iyo, Japan, during the entire year, the rain falls for 162.8 days and collects up to 749mm (29.49") of precipitation.

Snowfall

January, February and December are months with snowfall. December is the month with the most snowfall in Iyo. Snow falls for 1.2 days and accumulates 6mm (0.24") of snow.

Sea temperature

In Iyo, in December, the average water temperature is 18.3°C (64.9°F).
Note: Most people do not enjoy swimming in water of 18.3°C (64.9°F). Breathing control becomes harder as the temperature descends from 21°C (69.8°F) to 15°C (59°F).

Daylight

The month with the shortest days is December, with an average of 10h and 0min of daylight.
On the first day of December in Iyo, sunrise is at 06:55 and sunset at 17:00. On the last day of the month, sunrise is at 07:13 and sunset at 17:10 JST.

Sunshine

The average sunshine in December in Iyo is 5.3h.

UV index

The months with the lowest UV index are January and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a minimal health vulnerability from unsafe exposure to UV radiation for the average person.
Note: The maximum daily UV index of 2 during December translates into the following directions:
Babies, children, and those with sensitive skin should always avoid extended periods in the sun. To guard against the harmful effects of the Sun, minimize exposure during midday. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. Alert! The snow's reflection can amplify the UV radiation of the Sun nearly twice.

Frequently asked questions

In December, the average high-temperature and low-temperature in Iyo are 9.9°C (49.8°F) and 5°C (41°F) respectively. In August, the average heat index (a.k.a. 'real feel', 'feels like'), which combines air temperature and relative humidity, is computed to be 35°C (95°F).

The average relative humidity in December in Iyo, Japan, is 74%.

In December, in Iyo, Japan, the rain falls for 10.7 days. Throughout December, 38mm (1.5") of precipitation is accumulated.

December is the month with the most snowfall in Iyo, Japan. Snow falls for 1.2 days and accumulates 6mm (0.24") of snow.

December is the first month it typically snows in Iyo. Throughout December, in the average 1.2 snowfall days, it receives 6mm (0.24") of snow.

In Iyo, the average seawater temperature in December is 18.3°C (64.9°F). For most, swimming in 18.3°C (64.9°F) is not an enjoyable activity. Furthermore, controlling your breathing becomes progressively more difficult as the water temperature decreases from 21°C (69.8°F) to 15°C (59°F).

The month with the shortest days is December, with an average of 10h and 0min of daylight.

In Iyo, Japan, the average day length in December is 9h and 58min.

On the first day of December in Iyo, sunrise is at 06:55 and sunset at 17:00. On the last day of the month, sunrise is at 07:13 and sunset at 17:10 JST.

In December, the average sunshine duration in Iyo, Japan, is 5.3h.

January and December, with an average maximum UV index of 2, are months with the lowest UV index.

The average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a minimal hazard to health from exposure to the Sun's UV radiation.
Average high temperature
Average low temperature
Average wind speed
Average max. wind speed
Average wind speed gusts
Average humidity
Average rainfall
Average rainfall days
Average snowfall
Average snowfall days
Average sea temperature
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
Iyo, Japan

  • Average high temperature in December: 9.9°C

The warmest month (with the highest average high temperature) is August (29.2°C).
The month with the lowest average high temperature is January (8°C).

  • Average low temperature in December: 5°C

The month with the highest average low temperature is August (23.4°C).
The coldest month (with the lowest average low temperature) is January (2.9°C).

Average pressure in December
Iyo, Japan

  • Average pressure in December: 1020.6mbar

The month with the highest atmospheric pressure is January (1021mbar).
The month with the lowest atmospheric pressure is June (1008.4mbar).

Average wind speed in December
Iyo, Japan

  • Average wind speed in December: 11.9km/h

The windiest month (with the highest average wind speed) is January (12.2km/h).
The calmest month (with the lowest average wind speed) is June (6.6km/h).

Average humidity in December
Iyo, Japan

  • Average humidity in December: 74%

The month with the highest relative humidity is July (84%).
The months with the lowest relative humidity are January, February and March (72%).

Average rainfall in December
Iyo, Japan

  • Average rainfall in December: 38mm

The wettest month (with the highest rainfall) is June (149mm).
The driest month (with the least rainfall) is January (24mm).

Average rainfall days in December
Iyo, Japan

  • Average rainfall days in December: 10.7 days

The month with the highest number of rainy days is July (21.3 days).
The month with the least rainy days is January (8.3 days).

Average snowfall in December
Iyo, Japan

  • Average snowfall in December: 6mm

The month with the highest snowfall is December (6mm).
The months with the least snowfall are March, April, May, June, July, August, September, October and November (0mm).

Average snowfall days in December
Iyo, Japan

  • Average snowfall days in December: 1.2 days

The month with the highest number of snowfall days is January (1.3 days).
The months with the least snowfall days are April, May, June, July, August, September, October and November (0 days).

Average sea temperature in December
Iyo, Japan

  • Average sea temperature in December: 18.3°C

The best month for swimming (with the highest average sea temperature) is August (27.2°C).
The coldest month (with the lowest average sea temperature) is February (14.7°C).

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

  • Average daylight in December: 10h and 0min

The month with the longest days is June (Average daylight: 14h and 24min).
The month with the shortest days is December (Average daylight: 10h and 0min).

  • Average sunshine in December: 5h and 18min

The month with the most sunshine is August (Average sunshine: 10h and 48min).
The month with the least sunshine is January (Average sunshine: 5h and 12min).

Average sunshine days in December
Iyo, Japan

  • Average sunshine days in December: 17.5 days

The month with the most sunshine days is January (20.3 days).
The month with the least sunshine days is August (6.4 days).

Average UV index in December
Iyo, Japan

  • Average UV index in December: 2

The month with the highest UV index is July (UV index 7).
The months with the lowest UV index are January and December (UV index 2).

Average cloud cover in December
Iyo, Japan

  • Average cloud cover in December: 42

The month with the most cloud cover is January (Cloud cover 43).
The month with the least cloud cover is August (Cloud cover 30).

Average visibility in December
Iyo, Japan

  • Average visibility in December: 10km

The months with the highest visibility are January, February, March, August, September, October, November and December (10km).
The months with the lowest visibility are April, May, June and July (9km).