December weather forecastMerrillville, IN
December
Weather in December
December holds the onset of winter in Merrillville with temperatures dropping to an average low of 26.6°F (-3°C). Snowfall resumes after a break since April, covering everything in beautiful white. Although days are short, the bright winter sun combined with gleaming snow creates a stunning, festive vista. Not only does December mark the start of winter, it also rounds off the year with a hearty celebration of holidays and a promise of a fresh start to the seasons cycle in the coming year.Temperature
With December's arrival, Merrillville, Indiana, sees a decrease in average high-temperatures, moving from a frosty 47.1°F (8.4°C) in November to an icy 36°F (2.2°C). Merrillville records an average nighttime low-temperature of 26.6°F (-3°C) throughout December.Humidity
In Merrillville, the average relative humidity in December is 81%.Rainfall
In Merrillville, in December, it is raining for 7.7 days, with typically 1.1" (28mm) of accumulated precipitation. In Merrillville, during the entire year, the rain falls for 146.6 days and collects up to 23.31" (592mm) of precipitation.Snowfall
Months with snowfall are January through April, October through December. In Merrillville, in December, during 9.9 snowfall days, 2.2" (56mm) of snow is typically accumulated. In Merrillville, during the entire year, snow falls for 45.5 days and aggregates up to 12.64" (321mm) of snow.Daylight
With an average of 9h and 12min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 6:56 am and sunset at 4:20 pm. On the last day of December, in Merrillville, sunrise is at 7:15 am and sunset at 4:29 pm CST.
Sunshine
In December, the average sunshine is 3.9h.UV index
The months with the lowest UV index are January and December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV rays for average individuals.Note: An average UV index of 1 in December transforms into this advice:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. In the presence of strong sunlight, it's crucial to wear sunglasses that ward off UVA and UVB rays. Remember this! The UV radiation of the Sun can be nearly doubled by the reflective properties of snow.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Merrillville, IN
- Average high temperature in December: 36°F
The warmest month (with the highest average high temperature) is July (81.5°F).
The month with the lowest average high temperature is January (30°F).
- Average low temperature in December: 26.6°F
The month with the highest average low temperature is July (65.5°F).
The coldest month (with the lowest average low temperature) is January (18.9°F).
Average pressure in December
Merrillville, IN
- Average pressure in December: 30.09"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in December
Merrillville, IN
- Average wind speed in December: 9.6mph
The windiest month (with the highest average wind speed) is January (10.3mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).
Average humidity in December
Merrillville, IN
- Average humidity in December: 81%
The month with the highest relative humidity is February (83%).
The month with the lowest relative humidity is October (73%).
Average rainfall in December
Merrillville, IN
- Average rainfall in December: 1.1"
The wettest month (with the highest rainfall) is June (3.15").
The driest month (with the least rainfall) is November (1.06").
Average rainfall days in December
Merrillville, IN
- Average rainfall days in December: 7.7 days
The month with the highest number of rainy days is July (17.6 days).
The month with the least rainy days is February (5.3 days).
Average snowfall in December
Merrillville, IN
- Average snowfall in December: 2.2"
The month with the highest snowfall is February (3.5").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Merrillville, IN
- Average snowfall days in December: 9.9 days
The month with the highest number of snowfall days is January (12.4 days).
The months with the least snowfall days are May, June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Merrillville, IN
- Average daylight in December: 9h and 12min
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 12min).
- Average sunshine in December: 3h and 54min
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
Merrillville, IN
- Average sunshine days in December: 15.7 days
The month with the most sunshine days is November (17.4 days).
The month with the least sunshine days is July (10.2 days).
Average UV index in December
Merrillville, IN
- 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
Merrillville, IN
- 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
Merrillville, IN
- 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).
