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
A moderate decline in the average high-temperature is seen during December, decreasing from a fresh 51.3°F (10.7°C) in November to a cold 40.8°F (4.9°C). An average low-temperature of 29.5°F (-1.4°C) is noted during the month of December.Humidity
The average relative humidity in December in Sullivan is 80%.Rainfall
In Sullivan, in December, during 9.4 rainfall days, 2.24" (57mm) of precipitation is typically accumulated. Throughout the year, there are 150.1 rainfall days, and 28.5" (724mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, November and December. In Sullivan, in December, snow falls for 5.2 days, with typically accumulated 1.57" (40mm) of snow. Throughout the year, there are 23.8 snowfall days, and 6.89" (175mm) of snow is accumulated.Daylight
With an average of 9h and 30min of daylight, December has the shortest days of the year.On the first day of December, sunrise is at 7:50 am and sunset at 5:27 pm. On the last day of the month, sunrise is at 8:08 am and sunset at 5:37 pm EST.
Sunshine
The month with the least sunshine is December, with an average of 4.4h of sunshine.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 reading of 2, and below, represents a minimal health vulnerability from exposure to the Sun's UV radiation for the average person.Note: In December, the maximum UV index of 2 suggests this advice:
Children necessitate constant protection from sunlight, unlike the majority, who can remain under the sun for about an hour without burning. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. Sunglasses that guard against UVA and UVB rays are pivotal in minimizing sun-induced ocular damage. Be aware! The reflective nature of snow can magnify the Sun's UV radiation almost twofold.
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Data Sources | Weather Forecasting & Climate
Frequently asked questions
Is December cold?
What is the average humidity in December?
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 Sullivan have in December?
When are sunrise and sunset in December?
What is the month with the least sunshine?
How many hours of sunshine does Sullivan have in December?
What are the months with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Sullivan, IN
- Average high temperature in December: 40.8°F
The warmest month (with the highest average high temperature) is July (83.7°F).
The month with the lowest average high temperature is January (36°F).
- Average low temperature in December: 29.5°F
The month with the highest average low temperature is July (66.7°F).
The coldest month (with the lowest average low temperature) is January (23.2°F).
Average pressure in December
Sullivan, IN
- Average pressure in December: 30.13"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in December
Sullivan, IN
- Average wind speed in December: 8.9mph
The windiest months (with the highest average wind speed) are January and February (9.8mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).
Average humidity in December
Sullivan, IN
- Average humidity in December: 80%
The month with the highest relative humidity is July (82%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Sullivan, IN
- Average rainfall in December: 2.24"
The wettest month (with the highest rainfall) is April (4.06").
The driest month (with the least rainfall) is September (1.54").
Average rainfall days in December
Sullivan, IN
- Average rainfall days in December: 9.4 days
The month with the highest number of rainy days is May (18 days).
The month with the least rainy days is January (8.5 days).
Average snowfall in December
Sullivan, IN
- Average snowfall in December: 1.57"
The month with the highest snowfall is January (2.13").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Sullivan, IN
- Average snowfall days in December: 5.2 days
The month with the highest number of snowfall days is January (7.3 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in December /
Average sunshine in December
Sullivan, IN
- Average daylight in December: 9h and 3min
The month with the longest days is June (Average daylight: 14h and 54min).
The month with the shortest days is December (Average daylight: 9h and 30min).
- Average sunshine in December: 4h and 2min
The month with the most sunshine is June (Average sunshine: 10h and 24min).
The month with the least sunshine is December (Average sunshine: 4h and 24min).
Average sunshine days in December
Sullivan, IN
- Average sunshine days in December: 16.9 days
The month with the most sunshine days is November (18.7 days).
The month with the least sunshine days is May (10.1 days).
Average UV index in December
Sullivan, IN
- Average UV index in December: 2
The months with the highest UV index are May, June, July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover in December
Sullivan, IN
- Average cloud cover in December: 53
The month with the most cloud cover is January (Cloud cover 55).
The month with the least cloud cover is August (Cloud cover 29).
Average visibility in December
Sullivan, IN
- 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).
Sullivan, Indiana, USA
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