December weather forecastMerrill, IA
December
Weather in December
December, the first month of the winter in Merrill, is still a freezing cold month, with an average temperature ranging between max 29.3°F (-1.5°C) and min 17.8°F (-7.9°C).Temperature
Merrill in December showcases a distinct temperature shift, moving from an average high of a chilly 45.1°F (7.3°C) in November to a subzero cold 29.3°F (-1.5°C). Merrill experiences a steady low-temperature of 17.8°F (-7.9°C) throughout December.Humidity
In Merrill, the average relative humidity in December is 83%.Rainfall
In Merrill, during December, the rain falls for 2.6 days and regularly aggregates up to 0.79" (20mm) of precipitation. Throughout the year, in Merrill, Iowa, there are 112 rainfall days, and 15.71" (399mm) of precipitation is accumulated.Snowfall
January through April, October through December are months with snowfall. In Merrill, Iowa, during December, snow falls for 7.4 days and regularly aggregates up to 1.3" (33mm) of snow. In Merrill, during the entire year, snow falls for 34.7 days and aggregates up to 7.52" (191mm) of snow.Daylight
With an average of 9h and 6min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:36 am and sunset at 4:52 pm. On the last day of the month, sunrise is at 7:55 am and sunset at 5:01 pm CST.
Sunshine
In December, the average sunshine is 4.7h.UV index
The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a low threat to health from exposure to the Sun's UV radiation for average individuals.Note: A daily high UV index of 2 in December leads to these guidelines:
Prolonged sun exposure should always be prevented in babies, children, and those with sensitive skin. Given the potency of the midday Sun's UV radiation, one should avoid prolonged exposure. Consider a wide-brim hat essential for effective sun defense covering your face, neck, and eyes. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the snow.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Merrill, IA
- Average high temperature in December: 29.3°F
The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is January (25.2°F).
- Average low temperature in December: 17.8°F
The month with the highest average low temperature is July (64.2°F).
The coldest month (with the lowest average low temperature) is January (12.2°F).
Average pressure in December
Merrill, 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
Merrill, IA
- Average wind speed in December: 10.1mph
The windiest month (with the highest average wind speed) is April (11.1mph).
The calmest month (with the lowest average wind speed) is July (7.7mph).
Average humidity in December
Merrill, IA
- Average humidity in December: 83%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is October (66%).
Average rainfall in December
Merrill, IA
- Average rainfall in December: 0.79"
The wettest month (with the highest rainfall) is June (2.48").
The driest month (with the least rainfall) is January (0.35").
Average rainfall days in December
Merrill, IA
- Average rainfall days in December: 2.6 days
The month with the highest number of rainy days is June (16.5 days).
The months with the least rainy days are February and December (2.6 days).
Average snowfall in December
Merrill, IA
- Average snowfall in December: 1.3"
The month with the highest snowfall is February (1.85").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Merrill, IA
- Average snowfall days in December: 7.4 days
The month with the highest number of snowfall days is January (9.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Merrill, IA
- Average daylight in December: 9h and 6min
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 42min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The month with the least sunshine is January (Average sunshine: 4h and 12min).
Average sunshine days in December
Merrill, IA
- Average sunshine days in December: 21.8 days
The month with the most sunshine days is November (22.5 days).
The month with the least sunshine days is June (11.9 days).
Average UV index in December
Merrill, IA
- Average UV index in December: 2
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Merrill, IA
- Average cloud cover in December: 50
The month with the most cloud cover is January (Cloud cover 54).
The month with the least cloud cover is July (Cloud cover 26).
Average visibility in December
Merrill, 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).





