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
As November shifts into December, a slight alteration in temperatures is observed, with average highs reducing from a wintry 42.6°F (5.9°C) to a freezing cold 28.9°F (-1.7°C). In Castalia, December's nights observe an average temperature dip to 18.7°F (-7.4°C).Humidity
In Castalia, the average relative humidity in December is 85%.Rainfall
In Castalia, during December, the rain falls for 5.4 days and regularly aggregates up to 1.42" (36mm) of precipitation. In Castalia, Iowa, during the entire year, the rain falls for 131 days and collects up to 27.91" (709mm) of precipitation.Snowfall
January through May, October through December are months with snowfall in Castalia, Iowa. In Castalia, in December, snow falls for 11.9 days, with typically accumulated 4.06" (103mm) of snow. In Castalia, during the entire year, snow falls for 52.3 days and aggregates up to 21.26" (540mm) of snow.Daylight
December has the shortest days of the year in Castalia, with an average of 9h and 6min of daylight.On the first day of December in Castalia, sunrise is at 7:19 am and sunset at 4:32 pm. On the last day of the month, sunrise is at 7:38 am and sunset at 4:41 pm CST.
Sunshine
The average sunshine in December is 4h.UV index
January, November and December, with an average maximum UV index of 1, are months with the lowest UV index. A UV Index reading of 2, and below, represents a low health risk from exposure to the Sun's UV rays for ordinary individuals.Note: The maximum daily UV index of 1 during December translates into the following directions:
Although the majority can endure up to an hour in the sun without burns, children always require sun protection. The best time to avoid the Sun's harmful UV radiation is during midday when it's most potent. Fend off the sun's harsh rays with appropriate clothing, a wide-brim hat, and UV-protective sunglasses. Observe! Snow reflection can nearly intensify the Sun's UV radiation twofold.
Frequently asked questions
How cold is December in Castalia?
What is the average humidity in December in Castalia?
How many days does it rain in December in Castalia?
How many days does it snow in December in Castalia?
What is the month with the shortest days in Castalia?
What is the average length of the day in December in Castalia?
When are sunrise and sunset in December in Castalia?
How many hours of sunshine does Castalia have in December?
When is the lowest UV index in Castalia?
What is the UV index intensity in December in Castalia?
Average temperature in December
Castalia, IA
- Average high temperature in December: 28.9°F
The warmest month (with the highest average high temperature) is July (79°F).
The month with the lowest average high temperature is January (22.5°F).
- Average low temperature in December: 18.7°F
The month with the highest average low temperature is July (62.2°F).
The coldest month (with the lowest average low temperature) is January (9.9°F).
Average pressure in December
Castalia, IA
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is January (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in December
Castalia, IA
- Average wind speed in December: 9.8mph
The windiest month (with the highest average wind speed) is April (10.5mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).
Average humidity in December
Castalia, IA
- Average humidity in December: 85%
The month with the highest relative humidity is January (89%).
The month with the lowest relative humidity is October (75%).
Average rainfall in December
Castalia, IA
- Average rainfall in December: 1.42"
The wettest month (with the highest rainfall) is June (4.33").
The driest month (with the least rainfall) is January (0.98").
Average rainfall days in December
Castalia, IA
- Average rainfall days in December: 5.4 days
The month with the highest number of rainy days is June (17.7 days).
The month with the least rainy days is February (3.8 days).
Average snowfall in December
Castalia, IA
- Average snowfall in December: 4.06"
The month with the highest snowfall is February (5.16").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Castalia, IA
- Average snowfall days in December: 11.9 days
The month with the highest number of snowfall days is January (13.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Castalia, IA
- 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: 4h and 0min
The month with the most sunshine is August (Average sunshine: 9h and 48min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in December
Castalia, IA
- Average sunshine days in December: 16.8 days
The month with the most sunshine days is September (17 days).
The month with the least sunshine days is June (10.5 days).
Average UV index in December
Castalia, IA
- Average UV index in December: 1
The month with the highest UV index is July (UV index 6).
The months with the lowest UV index are January, November and December (UV index 1).
Average cloud cover in December
Castalia, IA
- Average cloud cover in December: 60
The month with the most cloud cover is January (Cloud cover 64).
The month with the least cloud cover is August (Cloud cover 32).
Average visibility in December
Castalia, IA
- Average visibility in December: 6mi
The months with the highest visibility are March, April, May, June, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February and July (5mi).
Castalia, Iowa, USA
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