January weather forecast
Fairfax, VA

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Weather in January

Beginning the calendar year in Fairfax, Virginia, the weather in January tends to have lower temperatures, compared to the impending warmth in succeeding months. January’s average high thermostat reading is 40.5°F (4.7°C). Being the first month of the year, the city has a moderate amount of rainfall with the bulk coming in from 10.4 days on average. The overall climatic conditions show a modest snowfall and a fair amount of sunlight hours. The weather transitions from these chilly conditions towards slightly warmer temperatures in February.

Temperature

With average temperatures fluctuating between a high of 40.5°F (4.7°C) and a low of 26.4°F (-3.1°C), January stands out as the coldest month.

Humidity

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

Rainfall

In January, the rain falls for 10.4 days. Throughout January, 2.09" (53mm) of precipitation is accumulated. Throughout the year, there are 162 rainfall days, and 31.65" (804mm) of precipitation is accumulated.

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

The average length of the day in January in Fairfax 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 in Fairfax are January, February, November and December, with an average maximum UV index of 2. A UV Index value of 2, and less, symbolizes a low health risk from unprotected exposure to Sun's UV rays for the average person.
Note: During January, 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. The Sun's radiation is especially intense around midday; try to stay in shade during this period. Your best bet for sun defense on the face, eyes, and neck is a hat with a wide brim. Be alert to the fact! The reflection from snow can nearly double the UV radiation of the Sun.
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Frequently asked questions

What is the coldest month in Fairfax?

Fairfax's January weather reaches an average high of 40.5°F (4.7°C) and an average low of 26.4°F (-3.1°C), making it the coldest month.

How cold is January in Fairfax?

January temperatures in Fairfax, Virginia, vary between a high-temperature of 40.5°F (4.7°C) and a low-temperature of 26.4°F (-3.1°C).

What is the average humidity in January in Fairfax?

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

How many days does it rain in January in Fairfax?

In Fairfax, in January, during 10.4 rainfall days, 2.09" (53mm) of precipitation is typically accumulated.

What is the snowiest month in Fairfax?

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

How many days does it snow in January in Fairfax?

In Fairfax, in January, snow falls for 5.6 days, with typically accumulated 3.54" (90mm) of snow.

How many hours of daylight does Fairfax have in January?

The average day length in January in Fairfax, Virginia, is 9h and 49min.

When 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 4:57 pm. On the last day of the month, sunrise is at 7:16 am and sunset at 5:28 pm EST.

What is the month with the least sunshine in Fairfax?

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

How long on average sun shines in January in Fairfax?

The average sunshine duration in January in Fairfax, Virginia, 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?

The average daily maximum UV index in January is 2. A UV Index of 2, and less, symbolizes a minimal health vulnerability 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 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 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).

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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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Fairfax, Virginia, USA

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