January weather forecast
Fairfax, VA

Weather in January

January, like December, in Fairfax, Virginia, is another cold winter month, with an average temperature varying between 26.4°F (-3.1°C) and 40.5°F (4.7°C).

Temperature

The coldest month is January, with an average high-temperature of 40.5°F (4.7°C) and an average low-temperature of 26.4°F (-3.1°C).

Humidity

The average relative humidity in January in Fairfax is 73%.

Rainfall

In Fairfax, during 10.4 rainfall days, 2.09" (53mm) of precipitation is typically accumulated. Throughout the year, in Fairfax, there are 162 rainfall days, and 31.65" (804mm) of precipitation is accumulated.

Snowfall

January through April, November and December are months with snowfall in Fairfax. January is the month with the most snowfall. Snow falls for 5.6 days and accumulates 3.54" (90mm) of snow.

Daylight

The average length of the day in January is 9h and 49min.
On the first day of the month, sunrise is at 7:27 am and sunset at 4:58 pm. On the last day of January, sunrise is at 7:15 am and sunset at 5:29 pm EST.

Sunshine

January, February and December, with an average of 5.2h of sunshine, are months with the least sunshine in Fairfax.

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 minimal health hazard from unprotected exposure to Sun's UV rays for ordinary individuals.
Note: In January, the average maximum UV index of 2 translate into the following recommendations:
People with sensitive skin, children, and babies should always be protected from prolonged sun exposure. The solar radiation is most powerful near the mid-day, so the exposure to the direct Sun should be reduced accordingly. A wide-brim hat offers excellent sun protection for the eyes, ears, face, and neck. Sunglasses with UVA and UVB protection significantly reduce eye damage from sun exposure. Tightly woven, loose-fitting clothes provide additional protection from the Sun. Beware! The strength of the UV rays is increased nearly double-fold by the reflection of the snow.
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FAQ

What is the coldest month in Fairfax?

January is the coldest month in Fairfax, Virginia, with an average high-temperature of 40.5°F (4.7°C) and an average low-temperature of 26.4°F (-3.1°C).

What is the average humidity in January in Fairfax?

In January, the average relative humidity in Fairfax, Virginia, is 73%.

How much does it rain in Fairfax in January?

In Fairfax, in January, it is raining for 10.4 days, with typically 2.09" (53mm) of accumulated precipitation.

What is the snowiest month in Fairfax?

January is the month with the most snowfall. Snow falls for 5.6 days and accumulates 3.54" (90mm) of snow.

How many days does it snow in January in Fairfax?

In January, in Fairfax, it is snowing for 5.6 days. Throughout January, 3.54" (90mm) of snow is accumulated.

How many hours of daylight does Fairfax have in January?

In Fairfax, the average day length in January is 9h and 49min.

What time are sunrise and sunset in January in Fairfax?

In January, on the first day of the month, sunrise is at 7:27 am and sunset at 4:58 pm. On the last day of the month, sunrise is at 7:15 am and sunset at 5:29 pm EST.

What is the month with the least sunshine in Fairfax?

January, February and December, with an average of 5.2h of sunshine, are months with the least sunshine.

How long on average sun shines in January in Fairfax?

In January, the average sunshine duration is 5.2h.

What are the months with the lowest UV index in Fairfax?

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

How high is the UV index in January in Fairfax?

In Fairfax, the average daily maximum UV index in January is 2. A UV Index reading of 2, and below, represents a low health threat from exposure to Sun's UV rays.
Average humidity
Average rainfall days
Average snowfall days
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in January
Fairfax, VA

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).

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Average pressure in January
Fairfax, VA

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).

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Average wind speed in January
Fairfax, VA

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).

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Average humidity in January
Fairfax, VA

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%).

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Average rainfall in January
Fairfax, VA

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").

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Average rainfall days in January
Fairfax, VA

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).

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Average snowfall in January
Fairfax, VA

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").

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Average snowfall days in January
Fairfax, VA

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).

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Average daylight in January /
Average sunshine in January
Fairfax, VA

Average daylight in January / Average sunshine in January - Fairfax, VA
  • Average daylight in January: 9h and 49min

The month with the longest days is June (Average daylight: 14h and 51min).
The month with the shortest days is December (Average daylight: 9h and 30min).

  • Average sunshine in January: 5h and 12min

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).

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Average sunshine days in January
Fairfax, VA

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).

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Average UV index in January
Fairfax, VA

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).

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Average cloud cover in January
Fairfax, VA

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).

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Average visibility in January
Fairfax, VA

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).

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