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
December implies a gentle temperature shift, with average high-temperatures reducing from November's cool 50.5°F (10.3°C) to an icy 39.7°F (4.3°C). Throughout December, Westfield anticipates an average low-temperature of 28.9°F (-1.7°C).Humidity
In December, the average relative humidity is 80%.Rainfall
In Westfield, during December, the rain falls for 6.5 days and regularly aggregates up to 0.79" (20mm) of precipitation. Throughout the year, there are 115.9 rainfall days, and 11.26" (286mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, November and December. The month with the most snowfall is December, when snow falls for 4 days and typically aggregates up to 0.47" (12mm) of snow.Daylight
December has the shortest days of the year, with an average of 9h and 24min of daylight.On the first day of the month, sunrise is at 6:53 am and sunset at 4:28 pm. On the last day of December, sunrise is at 7:12 am and sunset at 4:38 pm CST.
Sunshine
In Westfield, the average sunshine in December is 4.4h.UV index
December is the month with the lowest UV index in Westfield, with an average maximum UV index of 1. A UV Index reading of 2, and below, represents a low threat to health from exposure to the Sun's UV radiation for average individuals.Note: The UV index of 1 during December leads to these advisories:
Although prolonged sun exposure does not typically bother most people, children, babies, and those with sensitive skin should always have protection. Being exposed to the midday Sun can have harmful effects due to strong UV radiation; always take precautions. Sunglasses providing both UVA and UVB protection are non-negotiable on sunlit days. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
Published by: Weather U.S. | About Us
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?
When does it snow the most?
How many days does it snow in December?
What is the month with the shortest days?
How many hours of daylight does Westfield have in December?
When are sunrise and sunset in December?
How many hours of sunshine does Westfield have in December?
What is the month with the lowest UV index?
How high is the UV index in December?
Average temperature in December
Westfield, IL
- Average high temperature in December: 39.7°F
The warmest month (with the highest average high temperature) is July (82.9°F).
The month with the lowest average high temperature is January (34.7°F).
- Average low temperature in December: 28.9°F
The month with the highest average low temperature is July (66.4°F).
The coldest month (with the lowest average low temperature) is January (22.6°F).
Average pressure in December
Westfield, IL
- 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
Westfield, IL
- Average wind speed in December: 9.6mph
The windiest months (with the highest average wind speed) are January and February (10.4mph).
The calmest months (with the lowest average wind speed) are July and August (6.1mph).
Average humidity in December
Westfield, IL
- Average humidity in December: 80%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Westfield, IL
- Average rainfall in December: 0.79"
The wettest month (with the highest rainfall) is April (1.54").
The driest month (with the least rainfall) is February (0.47").
Average rainfall days in December
Westfield, IL
- Average rainfall days in December: 6.5 days
The month with the highest number of rainy days is May (14.9 days).
The month with the least rainy days is February (6 days).
Average snowfall in December
Westfield, IL
- Average snowfall in December: 0.47"
The month with the highest snowfall is December (0.47").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Westfield, IL
- Average snowfall days in December: 4 days
The month with the highest number of snowfall days is January (5.8 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
Westfield, IL
- Average daylight in December: 9h and 2min
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 24min).
- 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 January (Average sunshine: 4h and 6min).
Average sunshine days in December
Westfield, IL
- Average sunshine days in December: 20.8 days
The month with the most sunshine days is October (21.2 days).
The month with the least sunshine days is May (12.4 days).
Average UV index in December
Westfield, IL
- 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
Westfield, IL
- 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 June (Cloud cover 30).
Average visibility in December
Westfield, IL
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, September, October, November and December (6mi).
The month with the lowest visibility is August (5mi).
Westfield, Illinois, USA
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