December weather forecast
Harmondsworth, United Kingdom

December

Weather in December

December, the first month of the winter in Harmondsworth, is also a frosty month, with an average temperature ranging between max 7.9°C (46.2°F) and min 3.4°C (38.1°F).

Temperature

With December's arrival, Harmondsworth notes an average high-temperature of a chilly 7.9°C (46.2°F), closely following the trend of the preceding month. With a barely noticeable fluctuation in temperature, Harmondsworth reaches an average low of 3.4°C (38.1°F) during the December nights.

Humidity

The most humid month is December, with an average relative humidity of 89%.

Rainfall

In Harmondsworth, in December, it is raining for 8.2 days, with typically 16mm (0.63") of accumulated precipitation. Throughout the year, there are 109 rainfall days, and 156mm (6.14") of precipitation is accumulated.

Snowfall

January through March and December are months with snowfall in Harmondsworth. December is the first month it typically snows in Harmondsworth. Throughout December, in the average 1.1 snowfall days, it receives 5mm (0.2") of snow. Throughout the year, there are 5.6 snowfall days, and 18mm (0.71") of snow is accumulated.

Daylight

The month with the shortest days is December, with an average of 7h and 54min of daylight.
On the first day of the month, sunrise is at 7:45 am and sunset at 3:56 pm. On the last day of December, in Harmondsworth, sunrise is at 8:07 am and sunset at 4:02 pm GMT.

Sunshine

In December, the average sunshine in Harmondsworth is 4.3h.

UV index

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV rays for average individuals.
Note: An average UV index of 2 in December transforms into this advice:
The majority are not significantly affected by prolonged sun exposure. Infants, children, and those with fair skin must always have protection. The Sun's harshest UV rays are around midday; it's wise to seek shade and limit time outdoors. To best shield against UV radiation, choose sun-safe garments and dependable sunglasses. Bear in mind! The Sun's UV radiation can nearly double in intensity due to the reflective quality of snow.

Frequently asked questions

What are the temperatures in Harmondsworth in December?
Harmondsworth in December has an average high-temperature of 7.9°C (46.2°F) and an average low-temperature of 3.4°C (38.1°F).
What is the most humid month in Harmondsworth?
December is the most humid month in Harmondsworth, with an average relative humidity of 89%.
What is the average humidity in December in Harmondsworth?
The average relative humidity in December is 89%.
How many days does it rain in December in Harmondsworth?
In Harmondsworth, United Kingdom, during December, the rain falls for 8.2 days and regularly aggregates up to 16mm (0.63") of precipitation.
When does it start to snow in Harmondsworth?
December is the first month it typically snows in Harmondsworth, United Kingdom. Throughout December, in the average 1.1 snowfall days, it receives 5mm (0.2") of snow.
What is the month with the shortest days in Harmondsworth?
December has the shortest days of the year in Harmondsworth, United Kingdom, with an average of 7h and 54min of daylight.
How many hours of daylight does Harmondsworth have in December?
The average day length in December is 7h and 56min.
When is the sunrise / sunset in December in Harmondsworth?
On the first day of December in Harmondsworth, United Kingdom, sunrise is at 7:45 am and sunset at 3:56 pm. On the last day of the month, sunrise is at 8:07 am and sunset at 4:02 pm GMT.
How long on average sun shines in December in Harmondsworth?
In Harmondsworth, United Kingdom, the average sunshine duration in December is 4.3h.
What is the month with the lowest UV index in Harmondsworth?
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index.
What is the UV index intensity in December in Harmondsworth?
In December, the average daily maximum UV index in Harmondsworth is 2. A UV Index value of 2, and less, symbolizes a low health threat 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 daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility
Average temperature in December
Harmondsworth, United Kingdom
  • Average high temperature in December: 7.9°C

The warmest month (with the highest average high temperature) is July (22°C).
The month with the lowest average high temperature is January (6.8°C).

  • Average low temperature in December: 3.4°C

The month with the highest average low temperature is August (13.7°C).
The coldest month (with the lowest average low temperature) is January (1.9°C).

Average pressure in December
Harmondsworth, United Kingdom
  • Average pressure in December: 1014.5mbar

The month with the highest atmospheric pressure is September (1016.9mbar).
The month with the lowest atmospheric pressure is November (1010.5mbar).

Average wind speed in December
Harmondsworth, United Kingdom
  • Average wind speed in December: 17.1km/h

The windiest month (with the highest average wind speed) is February (17.5km/h).
The calmest months (with the lowest average wind speed) are July and September (12.7km/h).

Average humidity in December
Harmondsworth, United Kingdom
  • Average humidity in December: 89%

The month with the highest relative humidity is December (89%).
The months with the lowest relative humidity are July and August (74%).

Average rainfall in December
Harmondsworth, United Kingdom
  • Average rainfall in December: 16mm

The wettest month (with the highest rainfall) is June (21mm).
The driest months (with the least rainfall) are January, March, April and May (9mm).

Average rainfall days in December
Harmondsworth, United Kingdom
  • Average rainfall days in December: 8.2 days

The month with the highest number of rainy days is June (12.3 days).
The month with the least rainy days is January (6.8 days).

Average snowfall in December
Harmondsworth, United Kingdom
  • Average snowfall in December: 5mm

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

Average snowfall days in December
Harmondsworth, United Kingdom
  • Average snowfall days in December: 1.1 days

The month with the highest number of snowfall days is February (2 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).

Average daylight in December /
Average sunshine in December
Harmondsworth, United Kingdom
  • Average daylight in December: 7h and 5min

The month with the longest days is June (Average daylight: 16h and 36min).
The month with the shortest days is December (Average daylight: 7h and 54min).

  • Average sunshine in December: 4h and 2min

The month with the most sunshine is July (Average sunshine: 7h and 54min).
The month with the least sunshine is February (Average sunshine: 3h and 42min).

Average sunshine days in December
Harmondsworth, United Kingdom
  • Average sunshine days in December: 19.8 days

The month with the most sunshine days is October (20.2 days).
The months with the least sunshine days are June and July (14.2 days).

Average UV index in December
Harmondsworth, United Kingdom
  • Average UV index in December: 2

The months with the highest UV index are June and July (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in December
Harmondsworth, United Kingdom
  • Average cloud cover in December: 58

The month with the most cloud cover is February (Cloud cover 61).
The month with the least cloud cover is April (Cloud cover 49).

Average visibility in December
Harmondsworth, United Kingdom
  • Average visibility in December: 9km

The months with the highest visibility are January, February, March, April, May, June, July, August, September, October and December (9km).
The month with the lowest visibility is November (8km).

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