December weather forecast
San Jose, IL

Share

Weather in December

December, the first month of the winter in San Jose, is also a wintry month, with an average temperature ranging between max 36.9°F (2.7°C) and min 26.4°F (-3.1°C).

Temperature

Transition into December marks a drop in the average high-temperature, moving from a frosty 48.9°F (9.4°C) in November to a wintry 36.9°F (2.7°C). San Jose, in the month of December, anticipates a consistent average low-temperature of 26.4°F (-3.1°C).

Humidity

In San Jose, the average relative humidity in December is 79%.

Rainfall

In San Jose, Illinois, in December, during 6.6 rainfall days, 1.06" (27mm) of precipitation is typically accumulated. In San Jose, during the entire year, the rain falls for 131.4 days and collects up to 20.08" (510mm) of precipitation.

Snowfall

January through April, November and December are months with snowfall. In San Jose, during December, snow falls for 5.4 days and regularly aggregates up to 1.22" (31mm) of snow. In San Jose, during the entire year, snow falls for 25.8 days and aggregates up to 8.66" (220mm) of snow.

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 4:32 pm. On the last day of December, sunrise is at 7:21 am and sunset at 4:42 pm CST.

Sunshine

In December, the average sunshine is 4.4h.

UV index

The months with the lowest UV index are January, February, November and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a low health risk from unsafe exposure to UV radiation for the ordinary person.
Note: The UV index of 2 in December translates into these instructions:
While most can endure approximately an hour in the sun without burning, children always require protection from sunlight. Midday is the peak time for the Sun's radiation; stay in the shade and protect yourself. In bright sunlight, prioritize sunglasses that grant protection from UVA and UVB radiation. Take into account! The reflection from snow can nearly double the Sun's UV radiation intensity.
Updated: Aug 11, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is December?

In San Jose, 36.9°F (2.7°C) is the average high-temperature and 26.4°F (-3.1°C) is the average low-temperature during December. In August, the average heat index (a.k.a. 'felt air temperature', 'feels like'), which represents the influence of relative humidity on air temperature, is estimated at 87.8°F (31°C).

What is the average humidity in December?

The average relative humidity in December is 79%.

How many days does it rain in December?

In December, the rain falls for 6.6 days. Throughout December, 1.06" (27mm) of precipitation is accumulated.

How many days does it snow in December?

In December, it is snowing for 5.4 days. Throughout December, 1.22" (31mm) of snow is accumulated.

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 24min of daylight.

What is the average length of the day in December?

In San Jose, the average day length in December is 9h and 22min.

When is the sunrise / sunset in December?

In December, on the first day of the month, sunrise is at 7:02 am and sunset at 4:32 pm. On the last day of the month, sunrise is at 7:21 am and sunset at 4:42 pm CST.

How long on average sun shines in December?

In December, the average sunshine duration is 4.4h.

What are the months with the lowest UV index?

January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index.

How high is the UV index in December?

In San Jose, the average daily maximum UV index in December is 2. A UV Index estimate of 2, and below, represents a minimal hazard to health from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in December
San Jose, IL

Average temperature in December - San Jose, IL
  • Average high temperature in December: 36.9°F

The warmest month (with the highest average high temperature) is July (82°F).
The month with the lowest average high temperature is January (31.5°F).

  • Average low temperature in December: 26.4°F

The month with the highest average low temperature is July (65.3°F).
The coldest month (with the lowest average low temperature) is January (19.8°F).

Average pressure in December
San Jose, IL

Average pressure in December - San Jose, 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
San Jose, IL

Average wind speed in December - San Jose, IL
  • Average wind speed in December: 9.8mph

The windiest month (with the highest average wind speed) is April (10.6mph).
The calmest month (with the lowest average wind speed) is August (6.4mph).

Average humidity in December
San Jose, IL

Average humidity in December - San Jose, IL
  • Average humidity in December: 79%

The month with the highest relative humidity is July (84%).
The month with the lowest relative humidity is October (71%).

Average rainfall in December
San Jose, IL

Average rainfall in December - San Jose, IL
  • Average rainfall in December: 1.06"

The wettest month (with the highest rainfall) is May (2.83").
The driest month (with the least rainfall) is February (1.02").

Average rainfall days in December
San Jose, IL

Average rainfall days in December - San Jose, IL
  • Average rainfall days in December: 6.6 days

The month with the highest number of rainy days is May (17.7 days).
The month with the least rainy days is February (5.1 days).

Average snowfall in December
San Jose, IL

Average snowfall in December - San Jose, IL
  • Average snowfall in December: 1.22"

The month with the highest snowfall is January (2.87").
The months with the least snowfall are May, June, July, August, September and October (0").

Average snowfall days in December
San Jose, IL

Average snowfall days in December - San Jose, IL
  • Average snowfall days in December: 5.4 days

The month with the highest number of snowfall days is January (8.4 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
San Jose, IL

Average daylight in December / Average sunshine in December - San Jose, 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 2min

The month with the most sunshine is June (Average sunshine: 10h and 12min).
The month with the least sunshine is January (Average sunshine: 4h and 0min).

Average sunshine days in December
San Jose, IL

Average sunshine days in December - San Jose, IL
  • Average sunshine days in December: 19.7 days

The month with the most sunshine days is November (20 days).
The month with the least sunshine days is May (11.8 days).

Average UV index in December
San Jose, IL

Average UV index in December - San Jose, 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
San Jose, IL

Average cloud cover in December - San Jose, IL
  • Average cloud cover in December: 53

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
San Jose, IL

Average visibility in December - San Jose, 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).

San Jose, Illinois, USA

Weather forecast for your location

1. Click Locate me button
2. Allow the app to use your location