December weather forecastKeystone, IN
December
Weather in December
December, the first month of the winter in Keystone, is still a cold month, with an average temperature ranging between max 36.7°F (2.6°C) and min 27.3°F (-2.6°C).Temperature
Transition into December marks a drop in the average high-temperature, moving from a frosty 48.2°F (9°C) in November to a wintry 36.7°F (2.6°C). Throughout December, an average nighttime temperature of 27.3°F (-2.6°C) is experienced.Humidity
The months with the highest humidity are January, February and December, with an average relative humidity of 83%.Rainfall
In December, the rain falls for 8.1 days. Throughout December, 1.3" (33mm) of precipitation is accumulated. Throughout the year, there are 137.2 rainfall days, and 17.95" (456mm) of precipitation is accumulated.Snowfall
January through April, October through December are months with snowfall. In Keystone, in December, snow falls for 8.1 days, with typically accumulated 1.54" (39mm) of snow. Throughout the year, there are 35.6 snowfall days, and 7.64" (194mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 18min of daylight.On the first day of December, sunrise is at 7:46 am and sunset at 5:14 pm. On the last day of the month, sunrise is at 8:04 am and sunset at 5:24 pm EST.
Sunshine
In December, the average sunshine is 3.9h.UV index
The month with the lowest UV index is December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a minimal health vulnerability from unsafe exposure to UV radiation for average individuals.Note: In December, the maximum UV index of 1 transforms into these recommendations:
Extended sunlight exposure does not pose significant problems for most people, except for children, infants, and people with fair skin who always need shielding. Solar radiation is at its peak intensity during midday, so it's advisable to stay indoors or in the shade. Select sunglasses that boast both UVA and UVB protection to limit the adverse effects of the sun on the eyes. Be vigilant! The reflective nature of snow can increase the Sun's UV radiation nearly twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Keystone, IN
- Average high temperature in December: 36.7°F
The warmest month (with the highest average high temperature) is July (81.1°F).
The month with the lowest average high temperature is January (31.6°F).
- Average low temperature in December: 27.3°F
The month with the highest average low temperature is July (64°F).
The coldest month (with the lowest average low temperature) is January (20.1°F).
Average pressure in December
Keystone, IN
- Average pressure in December: 30.11"Hg
The months with the highest atmospheric pressure are January and November (30.12"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in December
Keystone, IN
- Average wind speed in December: 9.8mph
The windiest month (with the highest average wind speed) is January (10.7mph).
The calmest month (with the lowest average wind speed) is August (6mph).
Average humidity in December
Keystone, IN
- Average humidity in December: 83%
The months with the highest relative humidity are January, February and December (83%).
The month with the lowest relative humidity is October (74%).
Average rainfall in December
Keystone, IN
- Average rainfall in December: 1.3"
The wettest month (with the highest rainfall) is May (2.24").
The driest month (with the least rainfall) is February (0.98").
Average rainfall days in December
Keystone, IN
- Average rainfall days in December: 8.1 days
The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is February (5.4 days).
Average snowfall in December
Keystone, IN
- Average snowfall in December: 1.54"
The month with the highest snowfall is February (2.2").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Keystone, IN
- Average snowfall days in December: 8.1 days
The month with the highest number of snowfall days is January (9.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Keystone, IN
- Average daylight in December: 9h and 18min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in December: 3h and 54min
The month with the most sunshine is July (Average sunshine: 10h and 0min).
The month with the least sunshine is January (Average sunshine: 3h and 30min).
Average sunshine days in December
Keystone, IN
- Average sunshine days in December: 16.4 days
The month with the most sunshine days is November (18.9 days).
The month with the least sunshine days is May (11.3 days).
Average UV index in December
Keystone, IN
- Average UV index in December: 1
The months with the highest UV index are June, July and August (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in December
Keystone, IN
- Average cloud cover in December: 60
The month with the most cloud cover is January (Cloud cover 64).
The months with the least cloud cover are July and August (Cloud cover 33).
Average visibility in December
Keystone, IN
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, October, November and December (6mi).
The months with the lowest visibility are August and September (5mi).
