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 the transition into December, Saint Johns observes a decrease in the average high-temperature, falling from a cool 53.6°F (12°C) in November to a frosty 43.5°F (6.4°C). In the month of December, the average low-temperature usually rests at a freezing cold 31.1°F (-0.5°C).Humidity
The average relative humidity in December in Saint Johns is 77%.Rainfall
In Saint Johns, Illinois, in December, it is raining for 8.2 days, with typically 1.57" (40mm) of accumulated precipitation. In Saint Johns, during the entire year, the rain falls for 147.6 days and collects up to 29.17" (741mm) of precipitation.Snowfall
Months with snowfall in Saint Johns are January through April, November and December. In Saint Johns, in December, snow falls for 3.7 days, with typically accumulated 0.87" (22mm) of snow. In Saint Johns, during the entire year, snow falls for 18 days and aggregates up to 4.53" (115mm) of snow.Daylight
The month with the shortest days in Saint Johns is December, with an average of 9h and 36min of daylight.On the first day of the month, sunrise is at 6:54 am and sunset at 4:37 pm. On the last day of December, sunrise is at 7:12 am and sunset at 4:47 pm CST.
Sunshine
In Saint Johns, the average sunshine in December is 4.8h.UV index
The months with the lowest UV index in Saint Johns are January, February, November and December, with an average maximum UV index of 2. A UV Index estimate of 2, and below, represents a minimal health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.Note: A daily maximum UV index of 2 in December translates into the following instructions:
While sun exposure does not greatly affect most, individuals with fair skin, babies, and children always need vigilant safeguarding. Considering the strength of solar radiation at midday, one should avoid direct Sun exposure. Counter UV radiation's ill effects with clothing designed for sun safety and UV-resistant eyewear. Guard yourself! Snow reflection can almost double the UV radiation from the Sun.
Frequently asked questions
How cold is December in Saint Johns?
What is the average humidity in December in Saint Johns?
How much does it rain in Saint Johns in December?
How much does it snow in Saint Johns in December?
What is the month with the shortest days in Saint Johns?
What is the average length of the day in December in Saint Johns?
What time are sunrise and sunset in December in Saint Johns?
How long on average sun shines in December in Saint Johns?
When is the lowest UV index in Saint Johns?
How high is the UV index in December in Saint Johns?
Average temperature in December
Saint Johns, IL
- Average high temperature in December: 43.5°F
The warmest month (with the highest average high temperature) is July (87.3°F).
The month with the lowest average high temperature is January (38.8°F).
- Average low temperature in December: 31.1°F
The month with the highest average low temperature is July (68.7°F).
The coldest month (with the lowest average low temperature) is January (25.7°F).
Average pressure in December
Saint Johns, IL
- Average pressure in December: 30.14"Hg
The month with the highest atmospheric pressure is January (30.16"Hg).
The month with the lowest atmospheric pressure is June (29.93"Hg).
Average wind speed in December
Saint Johns, IL
- Average wind speed in December: 8.9mph
The windiest months (with the highest average wind speed) are January and February (9.6mph).
The calmest months (with the lowest average wind speed) are July and August (5.8mph).
Average humidity in December
Saint Johns, IL
- Average humidity in December: 77%
The month with the highest relative humidity is May (79%).
The month with the lowest relative humidity is October (71%).
Average rainfall in December
Saint Johns, IL
- Average rainfall in December: 1.57"
The wettest month (with the highest rainfall) is April (3.58").
The driest month (with the least rainfall) is January (1.5").
Average rainfall days in December
Saint Johns, IL
- Average rainfall days in December: 8.2 days
The month with the highest number of rainy days is May (17 days).
The month with the least rainy days is December (8.2 days).
Average snowfall in December
Saint Johns, IL
- Average snowfall in December: 0.87"
The month with the highest snowfall is February (1.5").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Saint Johns, IL
- Average snowfall days in December: 3.7 days
The month with the highest number of snowfall days is January (5.4 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
Saint Johns, IL
- Average daylight in December: 9h and 4min
The month with the longest days is June (Average daylight: 14h and 48min).
The month with the shortest days is December (Average daylight: 9h and 36min).
- Average sunshine in December: 4h and 5min
The month with the most sunshine is July (Average sunshine: 10h and 30min).
The month with the least sunshine is January (Average sunshine: 4h and 36min).
Average sunshine days in December
Saint Johns, IL
- Average sunshine days in December: 19.2 days
The months with the most sunshine days are October and November (19.5 days).
The month with the least sunshine days is May (11.4 days).
Average UV index in December
Saint Johns, 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
Saint Johns, IL
- Average cloud cover in December: 49
The months with the most cloud cover are January and February (Cloud cover 50).
The month with the least cloud cover is June (Cloud cover 28).
Average visibility in December
Saint Johns, IL
- Average visibility in December: 6mi
The months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
The months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Saint Johns, Illinois, USA
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