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
During Keystone's transition into December, the average high-temperature lessens, moving from a frosty 45.1°F (7.3°C) in November to an icy 32.7°F (0.4°C). Keystone, during December nights, observes an average temperature of 21.7°F (-5.7°C).Humidity
The average relative humidity in December is 81%.Rainfall
In Keystone, Iowa, in December, during 6.4 rainfall days, 1.5" (38mm) of precipitation is typically accumulated. Throughout the year, there are 139 rainfall days, and 29.49" (749mm) of precipitation is accumulated.Snowfall
January through May, October through December are months with snowfall. In Keystone, in December, during 8.5 snowfall days, 2.64" (67mm) of snow is typically accumulated. In Keystone, during the entire year, snow falls for 39 days and aggregates up to 16.69" (424mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 12min of daylight.On the first day of December, sunrise is at 7:17 am and sunset at 4:38 pm. On the last day of the month, sunrise is at 7:36 am and sunset at 4:47 pm CST.
Sunshine
In December, the average sunshine is 4.4h.UV index
The months with the lowest UV index in Keystone are January, February, October through December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for the average person.Note: In December, a daily UV index of 2 turns into the following recommendations:
Though the majority can handle prolonged sun exposure, it is crucial to always shield babies, children, and those with fair skin. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. For a sun-safe wardrobe, go for clothes that are tightly woven and generously sized. Observe! Snow reflection can nearly intensify the Sun's UV radiation twofold.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is it in December?
What is the average humidity in December in Keystone?
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 Keystone have in December?
When is the sunrise / sunset in December?
How long on average sun shines in December?
What is the month with the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Keystone, IA
- Average high temperature in December: 32.7°F
The warmest month (with the highest average high temperature) is July (80.8°F).
The month with the lowest average high temperature is January (25.9°F).
- Average low temperature in December: 21.7°F
The month with the highest average low temperature is July (64.4°F).
The coldest month (with the lowest average low temperature) is January (13.5°F).
Average pressure in December
Keystone, IA
- Average pressure in December: 30.11"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.89"Hg).
Average wind speed in December
Keystone, IA
- Average wind speed in December: 10.1mph
The windiest month (with the highest average wind speed) is April (10.8mph).
The calmest month (with the lowest average wind speed) is August (7mph).
Average humidity in December
Keystone, IA
- Average humidity in December: 81%
The month with the highest relative humidity is January (85%).
The month with the lowest relative humidity is October (72%).
Average rainfall in December
Keystone, IA
- Average rainfall in December: 1.5"
The wettest month (with the highest rainfall) is May (4.61").
The driest month (with the least rainfall) is January (1.18").
Average rainfall days in December
Keystone, IA
- Average rainfall days in December: 6.4 days
The month with the highest number of rainy days is June (19.3 days).
The month with the least rainy days is January (4.5 days).
Average snowfall in December
Keystone, IA
- Average snowfall in December: 2.64"
The month with the highest snowfall is January (5.24").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in December
Keystone, IA
- Average snowfall days in December: 8.5 days
The month with the highest number of snowfall days is February (10.6 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, IA
- Average daylight in December: 9h and 1min
The month with the longest days is June (Average daylight: 15h and 12min).
The month with the shortest days is December (Average daylight: 9h and 12min).
- Average sunshine in December: 4h and 2min
The month with the most sunshine is July (Average sunshine: 9h and 54min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).
Average sunshine days in December
Keystone, IA
- Average sunshine days in December: 18.2 days
The month with the most sunshine days is October (19.2 days).
The month with the least sunshine days is June (8.4 days).
Average UV index in December
Keystone, IA
- Average UV index in December: 2
The month with the highest UV index is June (UV index 6).
The months with the lowest UV index are January, February, October, November and December (UV index 2).
Average cloud cover in December
Keystone, IA
- Average cloud cover in December: 54
The month with the most cloud cover is January (Cloud cover 57).
The month with the least cloud cover is September (Cloud cover 30).
Average visibility in December
Keystone, IA
- Average visibility in December: 6mi
The months with the highest visibility are February, March, April, May, June, August, September, October, November and December (6mi).
The months with the lowest visibility are January and July (5mi).
Keystone, Iowa, USA
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