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
Weather in December
Temperature
December reports an average high-temperature of a still frosty 7.1°C (44.8°F), slightly varied from November's 9.1°C (48.4°F). Consistently, Castleknock reports average nighttime temperatures of 3.4°C (38.1°F) during December, a marginal step down from its daytime highs.Humidity
December is the most humid month, with an average relative humidity of 90%.Rainfall
In December, in Castleknock, the rain falls for 14.9 days. Throughout December, 47mm (1.85") of precipitation is accumulated. Throughout the year, in Castleknock, Ireland, there are 209.2 rainfall days, and 564mm (22.2") of precipitation is accumulated.Snowfall
January through March, November and December are months with snowfall. In Castleknock, in December, snow falls for 1.2 days, with typically accumulated 13mm (0.51") of snow. Throughout the year, in Castleknock, there are 7.1 snowfall days, and 56mm (2.2") of snow is accumulated.Daylight
With an average of 7h and 36min of daylight, December has the shortest days of the year in Castleknock.On the first day of December, sunrise is at 8:18 am and sunset at 4:10 pm. On the last day of the month, sunrise is at 8:40 am and sunset at 4:16 pm GMT.
Sunshine
In Castleknock, the average sunshine in December is 4.2h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index in Castleknock. A UV Index of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV rays for average individuals.Note: The UV index of 2 during December leads to these advisories:
While most people are not greatly affected by extended sun exposure, those with fair skin, babies, and children must always have protection. The Sun's UV radiation is especially harmful around midday, so reduce exposure and stay safe. A wide-brimmed hat is a shield, deflecting up to 50% of harmful UV radiation from eyes. Consider this! The reflection from snow can almost double the intensity of the Sun's UV radiation.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
What are December temperatures in Castleknock?
What is the most humid month in Castleknock?
What is the average humidity in December in Castleknock?
How many days does it rain in December in Castleknock?
How many days does it snow in December in Castleknock?
What is the month with the shortest days in Castleknock?
How many hours of daylight does Castleknock have in December?
When is the sunrise / sunset in December in Castleknock?
How many hours of sunshine does Castleknock have in December?
What is the month with the lowest UV index in Castleknock?
How high is the UV index in December in Castleknock?
Average temperature in December
Castleknock, Ireland
- Average high temperature in December: 7.1°C
The warmest month (with the highest average high temperature) is July (17.3°C).
The month with the lowest average high temperature is January (7°C).
- Average low temperature in December: 3.4°C
The month with the highest average low temperature is July (11.2°C).
The coldest month (with the lowest average low temperature) is February (2.5°C).
Average pressure in December
Castleknock, Ireland
- Average pressure in December: 1011mbar
The month with the highest atmospheric pressure is May (1016mbar).
The month with the lowest atmospheric pressure is November (1008.3mbar).
Average wind speed in December
Castleknock, Ireland
- Average wind speed in December: 21km/h
The windiest month (with the highest average wind speed) is January (21.1km/h).
The calmest months (with the lowest average wind speed) are June and July (13.6km/h).
Average humidity in December
Castleknock, Ireland
- Average humidity in December: 90%
The month with the highest relative humidity is December (90%).
The months with the lowest relative humidity are March, April and May (85%).
Average rainfall in December
Castleknock, Ireland
- Average rainfall in December: 47mm
The wettest month (with the highest rainfall) is August (71mm).
The driest month (with the least rainfall) is April (30mm).
Average rainfall days in December
Castleknock, Ireland
- Average rainfall days in December: 14.9 days
The month with the highest number of rainy days is August (24.2 days).
The month with the least rainy days is February (13.6 days).
Average snowfall in December
Castleknock, Ireland
- Average snowfall in December: 13mm
The month with the highest snowfall is February (19mm).
The months with the least snowfall are April, May, June, July, August, September and October (0mm).
Average snowfall days in December
Castleknock, Ireland
- Average snowfall days in December: 1.2 days
The month with the highest number of snowfall days is February (2.4 days).
The months with the least snowfall days are April, May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Castleknock, Ireland
- Average daylight in December: 7h and 4min
The month with the longest days is June (Average daylight: 16h and 54min).
The month with the shortest days is December (Average daylight: 7h and 36min).
- Average sunshine in December: 4h and 1min
The months with the most sunshine are April and May (Average sunshine: 6h and 42min).
The months with the least sunshine are February, October and November (Average sunshine: 3h and 54min).
Average sunshine days in December
Castleknock, Ireland
- Average sunshine days in December: 13 days
The month with the most sunshine days is January (13.2 days).
The month with the least sunshine days is August (3.4 days).
Average UV index in December
Castleknock, Ireland
- Average UV index in December: 2
The months with the highest UV index are May, June and August (UV index 4).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Castleknock, Ireland
- Average cloud cover in December: 58
The month with the most cloud cover is July (Cloud cover 64).
The month with the least cloud cover is April (Cloud cover 55).
Average visibility in December
Castleknock, Ireland
- Average visibility in December: 9km
The months with the highest visibility are January, February, March, April, May, June, October, November and December (9km).
The months with the lowest visibility are July, August and September (8km).
Castleknock, Ireland
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