Contents
- Weather in January
- Frequently asked questions
- Average temperature in January
- Average pressure in January
- Average wind speed in January
- Average humidity in January
- Average rainfall in January
- Average rainfall days in January
- Average snowfall in January
- Average snowfall days in January
- Average daylight in January
- Average sunshine in January
- Average sunshine days in January
- Average UV index in January
- Average cloud cover in January
- Average visibility in January
Weather in January
Temperature
January is Fairfax's coldest month, registering average high temperatures of 40.5°F (4.7°C) and lows of 26.4°F (-3.1°C).Humidity
In Fairfax, the average relative humidity in January is 73%.Rainfall
In Fairfax, in January, during 10.4 rainfall days, 2.09" (53mm) of precipitation is typically accumulated. In Fairfax, during the entire year, the rain falls for 162 days and collects up to 31.65" (804mm) of precipitation.Snowfall
Months with snowfall are January through April, November and December. The month with the most snowfall is January, when snow falls for 5.6 days and typically aggregates up to 3.54" (90mm) of snow.Daylight
In Fairfax, the average length of the day in January is 9h and 49min.On the first day of January, sunrise is at 7:27 am and sunset at 4:57 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 5:28 pm EST.
Sunshine
January, February and December, with an average of 5.2h of sunshine, are months with the least sunshine.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 reading of 2, and below, represents a low health risk from exposure to the Sun's UV radiation for the ordinary person.Note: The maximum daily UV index of 2 in January converts into the following recommendations:
Apart from children, who require continuous protection, most can endure sun exposure for up to an hour without experiencing burns. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Tightly woven clothing, when worn loosely, shields effectively against the Sun. Be attentive! The reflective property of snow can nearly double the Sun's UV radiation.
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
What month is the coldest?
Is January cold in Fairfax?
What is the average humidity in January?
How much does it rain in January?
When does it snow the most?
How much does it snow in January?
How many hours of daylight does Fairfax have in January?
When are sunrise and sunset in January?
What are the months with the least sunshine?
How many hours of sunshine does Fairfax have in January?
What is the month with the lowest UV index?
How high is the UV index in January?
Average temperature in January
Fairfax, VA
- Average high temperature in January: 40.5°F
The warmest month (with the highest average high temperature) is July (88°F).
The month with the lowest average high temperature is January (40.5°F).
- Average low temperature in January: 26.4°F
The month with the highest average low temperature is July (68.4°F).
The coldest month (with the lowest average low temperature) is January (26.4°F).
Average pressure in January
Fairfax, VA
- Average pressure in January: 30.11"Hg
The month with the highest atmospheric pressure is November (30.14"Hg).
The month with the lowest atmospheric pressure is June (29.95"Hg).
Average wind speed in January
Fairfax, VA
- Average wind speed in January: 7.1mph
The windiest month (with the highest average wind speed) is March (7.4mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in January
Fairfax, VA
- Average humidity in January: 73%
The months with the highest relative humidity are October and December (77%).
The month with the lowest relative humidity is July (71%).
Average rainfall in January
Fairfax, VA
- Average rainfall in January: 2.09"
The wettest month (with the highest rainfall) is August (3.78").
The driest month (with the least rainfall) is September (2.01").
Average rainfall days in January
Fairfax, VA
- Average rainfall days in January: 10.4 days
The months with the highest number of rainy days are May and August (17.3 days).
The month with the least rainy days is November (9.1 days).
Average snowfall in January
Fairfax, VA
- Average snowfall in January: 3.54"
The month with the highest snowfall is January (3.54").
The months with the least snowfall are May, June, July, August, September and October (0").
Average snowfall days in January
Fairfax, VA
- Average snowfall days in January: 5.6 days
The month with the highest number of snowfall days is January (5.6 days).
The months with the least snowfall days are May, June, July, August, September and October (0 days).
Average daylight in January /
Average sunshine in January
Fairfax, VA
- Average daylight in January: 9h and 5min
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 30min).
- Average sunshine in January: 5h and 1min
The month with the most sunshine is July (Average sunshine: 10h and 48min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 12min).
Average sunshine days in January
Fairfax, VA
- Average sunshine days in January: 17.4 days
The month with the most sunshine days is November (19.6 days).
The month with the least sunshine days is July (11.3 days).
Average UV index in January
Fairfax, VA
- Average UV index in January: 2
The months with the highest UV index are May, 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 January
Fairfax, VA
- Average cloud cover in January: 44
The month with the most cloud cover is March (Cloud cover 46).
The month with the least cloud cover is July (Cloud cover 30).
Average visibility in January
Fairfax, VA
- Average visibility in January: 6mi
The months with the highest visibility are January, February, March, April, June, July, August, September, October, November and December (6mi).
The month with the lowest visibility is May (5mi).
Fairfax, Virginia, USA
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