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
The arrival of December corresponds with a temperature reduction, down from November's frosty 49.6°F (9.8°C) to an icy 38.3°F (3.5°C). Mason City witnesses an average low-temperature of 27.1°F (-2.7°C) throughout the month of December.Humidity
The average relative humidity in December in Mason City is 78%.Rainfall
The month with the least rainfall is December, when the rain falls for 8.1 days and typically collects 1.46" (37mm) of precipitation.Snowfall
January through April, October through December are months with snowfall in Mason City. In Mason City, during December, snow falls for 6 days and regularly aggregates up to 1.65" (42mm) of snow. Throughout the year, there are 31.9 snowfall days, and 11.06" (281mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 24min of daylight.On the first day of the month, sunrise is at 7:02 am and sunset at 4:33 pm. On the last day of December, sunrise is at 7:21 am and sunset at 4:43 pm CST.
Sunshine
The average sunshine in December is 4.6h.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index of 2, and less, symbolizes a low threat to health from unprotected exposure to Sun's UV rays for average individuals.Note: A daily high UV index of 2 in December leads to these guidelines:
Extended sun exposure is not an issue for the majority. Children, infants, and fair-skinned individuals always need to be protected. Sun's radiation is most powerful around mid-day, so it's best to limit outdoor activities during this time. For holistic sun protection encompassing the eyes, ears, face, and neck, a wide-brim hat is key. Remember! The Sun's UV radiation can be magnified almost twofold by the reflection of snow.
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?
What is the driest month?
How much does it rain in December?
How much does it snow in December?
What is the month with the shortest days in Mason City?
What is the average length of the day 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 in Mason City?
Average temperature in December
Mason City, IL
- Average high temperature in December: 38.3°F
The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (32°F).
- Average low temperature in December: 27.1°F
The month with the highest average low temperature is July (65.8°F).
The coldest month (with the lowest average low temperature) is January (19.9°F).
Average pressure in December
Mason City, IL
- Average pressure in December: 30.12"Hg
The month with the highest atmospheric pressure is January (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.91"Hg).
Average wind speed in December
Mason City, IL
- Average wind speed in December: 9.7mph
The windiest month (with the highest average wind speed) is April (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.3mph).
Average humidity in December
Mason City, IL
- Average humidity in December: 78%
The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (70%).
Average rainfall in December
Mason City, IL
- Average rainfall in December: 1.46"
The wettest month (with the highest rainfall) is May (3.98").
The driest month (with the least rainfall) is December (1.46").
Average rainfall days in December
Mason City, IL
- Average rainfall days in December: 8.1 days
The month with the highest number of rainy days is May (18.9 days).
The month with the least rainy days is February (6.2 days).
Average snowfall in December
Mason City, IL
- Average snowfall in December: 1.65"
The month with the highest snowfall is January (3.98").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Mason City, IL
- Average snowfall days in December: 6 days
The month with the highest number of snowfall days is January (10.7 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
Mason City, IL
- Average daylight in December: 9h and 2min
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 24min).
- Average sunshine in December: 4h and 4min
The month with the most sunshine is June (Average sunshine: 10h and 18min).
The month with the least sunshine is January (Average sunshine: 4h and 6min).
Average sunshine days in December
Mason City, IL
- Average sunshine days in December: 18 days
The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is May (10.5 days).
Average UV index in December
Mason City, IL
- Average UV index in December: 2
The months with the highest UV index are 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
Mason City, IL
- 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 August and September (Cloud cover 29).
Average visibility in December
Mason City, IL
- 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).
Mason City, Illinois, USA
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