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
The onset of December marks a clear decrease in the average high-temperature, dropping from a frosty 44.1°F (6.7°C) in November to a freezing cold 28.8°F (-1.8°C). Alton encounters an average low-temperature of 17.4°F (-8.1°C) during December nights.Humidity
In December, the average relative humidity is 84%.Rainfall
In Alton, in December, it is raining for 4.5 days, with typically 1.42" (36mm) of accumulated precipitation. In Alton, during the entire year, the rain falls for 124 days and collects up to 24.09" (612mm) of precipitation.Snowfall
January through May, October through December are months with snowfall. In Alton, during December, snow falls for 11 days and regularly aggregates up to 3.11" (79mm) of snow. Throughout the year, in Alton, there are 49.5 snowfall days, and 18.39" (467mm) of snow is accumulated.Daylight
December has the shortest days of the year in Alton, with an average of 9h and 6min of daylight.On the first day of December in Alton, sunrise is at 7:36 am and sunset at 4:50 pm. On the last day of the month, sunrise is at 7:55 am and sunset at 4:59 pm CST.
Sunshine
In Alton, the average sunshine in December is 4.4h.UV index
January and December, with an average maximum UV index of 1, are months with the lowest UV index in Alton. A UV Index reading of 2, and below, represents a minimal health vulnerability from unsafe exposure to UV radiation for ordinary individuals.Note: The daily maximum UV index of 1 in December interprets into the following advice:
Most individuals can handle sun exposure for up to an hour without burning, but children must always be shielded from sun exposure. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage. Guard yourself! Snow reflection can almost double the UV radiation from the Sun.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What is the average humidity in December in Alton?
How many days does it rain in December?
How much does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Alton have in December?
What time are sunrise and sunset in December?
How long on average sun shines in December?
What is the month with the lowest UV index?
How high is the UV index in December?
Average temperature in December
Alton, IA
- Average high temperature in December: 28.8°F
The warmest month (with the highest average high temperature) is July (81.7°F).
The month with the lowest average high temperature is January (24.6°F).
- Average low temperature in December: 17.4°F
The month with the highest average low temperature is July (63.3°F).
The coldest month (with the lowest average low temperature) is January (11.3°F).
Average pressure in December
Alton, IA
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.86"Hg).
Average wind speed in December
Alton, IA
- Average wind speed in December: 10.2mph
The windiest month (with the highest average wind speed) is April (11.3mph).
The calmest month (with the lowest average wind speed) is July (7.8mph).
Average humidity in December
Alton, IA
- Average humidity in December: 84%
The month with the highest relative humidity is January (86%).
The month with the lowest relative humidity is October (67%).
Average rainfall in December
Alton, IA
- Average rainfall in December: 1.42"
The wettest month (with the highest rainfall) is June (3.82").
The driest month (with the least rainfall) is January (0.79").
Average rainfall days in December
Alton, IA
- Average rainfall days in December: 4.5 days
The month with the highest number of rainy days is June (18 days).
The month with the least rainy days is February (2.8 days).
Average snowfall in December
Alton, IA
- Average snowfall in December: 3.11"
The month with the highest snowfall is February (4.61").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Alton, IA
- Average snowfall days in December: 11 days
The month with the highest number of snowfall days is January (12.1 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Alton, 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 2min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is January (Average sunshine: 3h and 54min).
Average sunshine days in December
Alton, IA
- Average sunshine days in December: 17.4 days
The month with the most sunshine days is November (20.3 days).
The month with the least sunshine days is June (9.3 days).
Average UV index in December
Alton, IA
- Average UV index in December: 1
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January and December (UV index 1).
Average cloud cover in December
Alton, IA
- Average cloud cover in December: 53
The month with the most cloud cover is January (Cloud cover 56).
The month with the least cloud cover is July (Cloud cover 28).
Average visibility in December
Alton, IA
- Average visibility in December: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
Alton, Iowa, USA
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