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 onset of December coincides with a reduction in the average high-temperature, falling from a frosty 46.9°F (8.3°C) in November to a wintry 35.6°F (2°C). December's nights observe an average temperature of 25.9°F (-3.4°C).Humidity
In Harvey, the average relative humidity in December is 81%.Rainfall
The month with the least rainfall is December, when the rain falls for 7.9 days and typically collects 1.54" (39mm) of precipitation.Snowfall
January through April, October through December are months with snowfall. In Harvey, Illinois, during December, snow falls for 9.1 days and regularly aggregates up to 2.76" (70mm) of snow. Throughout the year, there are 44.6 snowfall days, and 16.46" (418mm) of snow is accumulated.Daylight
The month with the shortest days is December, with an average of 9h and 12min of daylight.On the first day of the month, sunrise is at 6:58 am and sunset at 4:21 pm. On the last day of December, sunrise is at 7:17 am and sunset at 4:30 pm CST.
Sunshine
The average sunshine in December is 4h.UV index
December is the month with the lowest UV index, with an average maximum UV index of 1. A UV Index reading of 2, and below, represents a minimal health vulnerability from unsafe exposure to UV radiation for the average person.Note: The maximum UV index of 1 during December translates into these guidelines:
For the majority, extended sun exposure is not of great concern. Infants and people with sensitive skin must always be protected. Exposing oneself to the midday Sun can be harmful due to the strong UV radiation; limit your time outside. Experience reduced UV exposure by about half when donning a wide-brim hat. Be advised! The UV radiation from the Sun can be almost doubled due to the reflective properties 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 many days does it rain in December?
How many days does it snow in December?
What is the month with the shortest days?
What is the average length of the day in December?
When is the sunrise / sunset in December in Harvey?
How many hours of sunshine does Harvey have in December?
What is the month with the lowest UV index?
How high is the UV index in December?
Average temperature in December
Harvey, IL
- Average high temperature in December: 35.6°F
The warmest month (with the highest average high temperature) is July (81.3°F).
The month with the lowest average high temperature is January (29.7°F).
- Average low temperature in December: 25.9°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 (18.9°F).
Average pressure in December
Harvey, IL
- Average pressure in December: 30.1"Hg
The month with the highest atmospheric pressure is January (30.11"Hg).
The month with the lowest atmospheric pressure is June (29.92"Hg).
Average wind speed in December
Harvey, IL
- Average wind speed in December: 9.5mph
The windiest month (with the highest average wind speed) is January (10.2mph).
The calmest month (with the lowest average wind speed) is August (6.3mph).
Average humidity in December
Harvey, IL
- Average humidity in December: 81%
The months with the highest relative humidity are January and February (82%).
The month with the lowest relative humidity is October (73%).
Average rainfall in December
Harvey, IL
- Average rainfall in December: 1.54"
The wettest month (with the highest rainfall) is May (4.17").
The driest month (with the least rainfall) is December (1.54").
Average rainfall days in December
Harvey, IL
- Average rainfall days in December: 7.9 days
The month with the highest number of rainy days is July (17.6 days).
The month with the least rainy days is February (6.1 days).
Average snowfall in December
Harvey, IL
- Average snowfall in December: 2.76"
The month with the highest snowfall is January (4.53").
The months with the least snowfall are May, June, July, August and September (0").
Average snowfall days in December
Harvey, IL
- Average snowfall days in December: 9.1 days
The month with the highest number of snowfall days is January (12.6 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in December /
Average sunshine in December
Harvey, IL
- Average daylight in December: 9h and 1min
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 0min
The month with the most sunshine is August (Average sunshine: 10h and 6min).
The month with the least sunshine is January (Average sunshine: 3h and 36min).
Average sunshine days in December
Harvey, IL
- Average sunshine days in December: 15 days
The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is April (10.2 days).
Average UV index in December
Harvey, IL
- Average UV index in December: 1
The months with the highest UV index are June and July (UV index 6).
The month with the lowest UV index is December (UV index 1).
Average cloud cover in December
Harvey, IL
- Average cloud cover in December: 59
The month with the most cloud cover is January (Cloud cover 62).
The month with the least cloud cover is August (Cloud cover 30).
Average visibility in December
Harvey, IL
- Average visibility in December: 6mi
The months with the highest visibility are February, March, April, May, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is January (5mi).
Harvey, Illinois, USA
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