December weather forecastSully, IA
December
Weather in December
December, the first month of the winter in Sully, is also a wintry month, with an average temperature fluctuating between 33.8°F (1°C) and 22.1°F (-5.5°C).Temperature
December indicates a shift in the average high-temperature, from November's chilly 46.9°F (8.3°C) to a cold 33.8°F (1°C). Sully witnesses a consistent average low-temperature of 22.1°F (-5.5°C) throughout December.Humidity
The average relative humidity in December in Sully, Iowa, is 80%.Rainfall
The months with the least rainfall in Sully, Iowa, are January, February and December Rain falls for 4.3 days and accumulates 0.39" (10mm) of rain.Snowfall
January through May, October through December are months with snowfall in Sully. In December, in Sully, it is snowing for 5 days. Throughout December, 0.51" (13mm) of snow is accumulated. Throughout the year, there are 28.8 snowfall days, and 5.28" (134mm) of snow is accumulated.Daylight
December has the shortest days of the year in Sully, with an average of 9h and 12min of daylight.On the first day of December, sunrise is at 7:19 am and sunset at 4:42 pm. On the last day of the month, sunrise is at 7:37 am and sunset at 4:51 pm CST.
Sunshine
The average sunshine in December in Sully, Iowa, is 4.7h.UV index
The months with the lowest UV index in Sully are January and December, with an average maximum UV index of 1. A UV Index estimate of 2, and below, represents a low threat to health from unsafe exposure to UV radiation for average individuals.Note: An average UV index of 1 in December transforms into this advice:
Most people can stay in the Sun for up to 1 hour without burning, apart from children that always must be protected from sun exposure. Direct exposure to the Sun during its peak hours around mid-day should be minimized for safety. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Take into account! The reflection from snow can nearly double the Sun's UV radiation intensity.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
Average temperature in December
Sully, IA
- Average high temperature in December: 33.8°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 (27.1°F).
- Average low temperature in December: 22.1°F
The month with the highest average low temperature is July (64.8°F).
The coldest month (with the lowest average low temperature) is January (14.4°F).
Average pressure in December
Sully, IA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in December
Sully, IA
- Average wind speed in December: 10mph
The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest months (with the lowest average wind speed) are July and August (7mph).
Average humidity in December
Sully, IA
- Average humidity in December: 80%
The month with the highest relative humidity is January (84%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Sully, IA
- Average rainfall in December: 0.39"
The wettest month (with the highest rainfall) is May (2.13").
The driest months (with the least rainfall) are January, February and December (0.39").
Average rainfall days in December
Sully, IA
- Average rainfall days in December: 4.3 days
The month with the highest number of rainy days is May (14.7 days).
The month with the least rainy days is February (3.4 days).
Average snowfall in December
Sully, IA
- Average snowfall in December: 0.51"
The month with the highest snowfall is January (1.73").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Sully, IA
- Average snowfall days in December: 5 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
Sully, IA
- 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: 4h and 42min
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 12min).
Average sunshine days in December
Sully, IA
- Average sunshine days in December: 22.9 days
The month with the most sunshine days is December (22.9 days).
The month with the least sunshine days is June (12.2 days).
Average UV index in December
Sully, IA
- 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
Sully, IA
- Average cloud cover in December: 51
The month with the most cloud cover is January (Cloud cover 55).
The months with the least cloud cover are July and September (Cloud cover 30).
Average visibility in December
Sully, IA
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, September, October, November and December (6mi).
The months with the lowest visibility are July and August (5mi).
