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 shift from November to December involves a decrease in the average high-temperature, from a chilly 47.5°F (8.6°C) to a cold 34.3°F (1.3°C). In December, Mercer reports a consistent average low-temperature of 22.1°F (-5.5°C) during the nights.Humidity
The average relative humidity in December is 79%.Rainfall
In December, the rain falls for 4.7 days. Throughout December, 0.63" (16mm) of precipitation is accumulated. Throughout the year, there are 115.1 rainfall days, and 19.21" (488mm) of precipitation is accumulated.Snowfall
January through April, October through December are months with snowfall. In Mercer, during December, snow falls for 5.3 days and regularly aggregates up to 1.22" (31mm) of snow. In Mercer, during the entire year, snow falls for 27.6 days and aggregates up to 8.15" (207mm) of snow.Daylight
With an average of 9h and 18min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:24 am and sunset at 4:51 pm. On the last day of the month, sunrise is at 7:43 am and sunset at 5:00 pm CST.
Sunshine
The average sunshine in December in Mercer is 4.9h.UV index
In Mercer, the average daily maximum UV index in December is 2. A UV Index reading of 2, and below, represents a low threat to health from unsafe exposure to UV radiation for average individuals.Note: In December, the maximum UV index of 2 translates into these guidelines:
Although prolonged sun exposure does not typically bother most people, children, babies, and those with sensitive skin should always have protection. Solar radiation peaks around mid-day, so it's wise to limit exposure to the Sun at this time. Sun protection is enhanced with clothing that boasts a tight weave yet offers a loose fit. Heed this! Snow reflection can almost augment the UV radiation of the sun by double.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in December?
What is the average humidity in December?
How much 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 Mercer have in December?
When is the sunrise / sunset in December?
How many hours of sunshine does Mercer have in December?
What is the UV index intensity in December?
Average temperature in December
Mercer, IA
- Average high temperature in December: 34.3°F
The warmest month (with the highest average high temperature) is July (83.3°F).
The month with the lowest average high temperature is January (29.3°F).
- Average low temperature in December: 22.1°F
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (16°F).
Average pressure in December
Mercer, 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 (29.88"Hg).
Average wind speed in December
Mercer, IA
- Average wind speed in December: 9.9mph
The windiest months (with the highest average wind speed) are March and April (10.5mph).
The calmest month (with the lowest average wind speed) is July (7mph).
Average humidity in December
Mercer, IA
- Average humidity in December: 79%
The months with the highest relative humidity are January and June (81%).
The month with the lowest relative humidity is October (70%).
Average rainfall in December
Mercer, IA
- Average rainfall in December: 0.63"
The wettest month (with the highest rainfall) is June (3.74").
The driest month (with the least rainfall) is February (0.51").
Average rainfall days in December
Mercer, IA
- Average rainfall days in December: 4.7 days
The month with the highest number of rainy days is May (16.5 days).
The month with the least rainy days is February (3 days).
Average snowfall in December
Mercer, IA
- Average snowfall in December: 1.22"
The month with the highest snowfall is January (2.28").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Mercer, IA
- Average snowfall days in December: 5.3 days
The month with the highest number of snowfall days is January (8.4 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Mercer, IA
- Average daylight in December: 9h and 2min
The month with the longest days is June (Average daylight: 15h and 6min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in December: 4h and 5min
The month with the most sunshine is July (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 24min).
Average sunshine days in December
Mercer, IA
- Average sunshine days in December: 21.9 days
The month with the most sunshine days is November (22.5 days).
The month with the least sunshine days is May (12 days).
Average UV index in December
Mercer, IA
- Average UV index in December: 2
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is January (UV index 1).
Average cloud cover in December
Mercer, IA
- Average cloud cover in December: 47
The month with the most cloud cover is January (Cloud cover 52).
The months with the least cloud cover are July and September (Cloud cover 29).
Average visibility in December
Mercer, IA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Mercer, Iowa, USA
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