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
As December commences, the average high-temperature shows a reduction, transitioning from a fresh 50.2°F (10.1°C) in November to an icy 39.6°F (4.2°C). Riley sees an average low-temperature of 28.6°F (-1.9°C) during December.Humidity
In December, the average relative humidity is 81%.Rainfall
In December, the rain falls for 9.4 days. Throughout December, 1.85" (47mm) of precipitation is accumulated. Throughout the year, there are 147.1 rainfall days, and 25.87" (657mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, November and December. December is the month with the most snowfall. Snow falls for 4.8 days and accumulates 1.85" (47mm) of snow.Daylight
With an average of 9h and 24min of daylight, December has the shortest days of the year.On the first day of the month, sunrise is at 7:50 am and sunset at 5:26 pm. On the last day of December, sunrise is at 8:09 am and sunset at 5:35 pm EST.
Sunshine
In December, the average sunshine is 4.4h.UV index
January, February, October through December, with an average maximum UV index of 2, are months with the lowest UV index in Riley. A UV Index reading of 2, and below, represents a minimal health vulnerability from unprotected exposure to Sun's UV rays for the ordinary person.Note: During December, 2 as the daily maximum UV index converts into the following advice:
Though extended exposure to the sun typically does not concern most people, it is crucial to always shield children, infants, and those with sensitive skin. It's crucial to reduce time in the direct Sun around mid-day due to the intense solar radiation. Sun-related eye harm can be minimized with proper sunglasses offering UVA and UVB coverage. Alert! The snow's reflection can amplify the UV radiation of the Sun nearly twice.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
How cold is December?
What is the average humidity in December?
How much does it rain in December?
When does it snow the most in Riley?
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 Riley?
How long on average sun shines in December?
When is the lowest UV index?
What is the UV index reading in December?
Average temperature in December
Riley, IN
- Average high temperature in December: 39.6°F
The warmest month (with the highest average high temperature) is July (82.8°F).
The month with the lowest average high temperature is January (34.3°F).
- Average low temperature in December: 28.6°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 (22.1°F).
Average pressure in December
Riley, IN
- 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
Riley, IN
- Average wind speed in December: 9.1mph
The windiest months (with the highest average wind speed) are January and February (9.9mph).
The calmest months (with the lowest average wind speed) are July and August (5.9mph).
Average humidity in December
Riley, IN
- Average humidity in December: 81%
The month with the highest relative humidity is July (83%).
The month with the lowest relative humidity is October (72%).
Average rainfall in December
Riley, IN
- Average rainfall in December: 1.85"
The wettest month (with the highest rainfall) is April (3.62").
The driest month (with the least rainfall) is February (1.42").
Average rainfall days in December
Riley, IN
- Average rainfall days in December: 9.4 days
The month with the highest number of rainy days is May (19 days).
The month with the least rainy days is February (7.8 days).
Average snowfall in December
Riley, IN
- Average snowfall in December: 1.85"
The month with the highest snowfall is December (1.85").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in December
Riley, IN
- Average snowfall days in December: 4.8 days
The month with the highest number of snowfall days is January (6.9 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
Riley, IN
- 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 12min).
The month with the least sunshine is January (Average sunshine: 4h and 18min).
Average sunshine days in December
Riley, IN
- Average sunshine days in December: 17.7 days
The month with the most sunshine days is November (19 days).
The month with the least sunshine days is May (9.3 days).
Average UV index in December
Riley, IN
- 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, October, November and December (UV index 2).
Average cloud cover in December
Riley, IN
- Average cloud cover in December: 54
The month with the most cloud cover is January (Cloud cover 57).
The months with the least cloud cover are June, August and September (Cloud cover 31).
Average visibility in December
Riley, IN
- 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).
Riley, Indiana, USA
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