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
The coldest time of the year is January, with temperatures averaging a high of 39.7°F (4.3°C) and a low of 25.9°F (-3.4°C).Humidity
In January, the average relative humidity is 74%.Rainfall
In Herndon, in January, during 9.3 rainfall days, 2.13" (54mm) of precipitation is typically accumulated. Throughout the year, there are 158.1 rainfall days, and 31.46" (799mm) of precipitation is accumulated.Snowfall
Months with snowfall are January through April, November and December. The month with the most snowfall in Herndon is January, when snow falls for 5.1 days and typically aggregates up to 3.54" (90mm) of snow.Daylight
The average length of the day in January in Herndon, Virginia, is 9h and 48min.On the first day of the month, sunrise is at 7:28 am and sunset at 4:57 pm. On the last day of January, in Herndon, sunrise is at 7:16 am and sunset at 5:29 pm EST.
Sunshine
January, February and December, with an average of 5h of sunshine, are months with the least sunshine in Herndon.UV index
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index. A UV Index reading of 2, and below, represents a low threat to health from unsafe exposure to UV radiation for average individuals.Note: In January, a regular UV index of 2 translates into these guidelines:
Despite most people tolerating extended sun exposure, it is critical to always protect those with sensitive skin, infants, and children. The Sun's most intense and consequently most harmful UV radiation during midday hours should be decreased by minimizing exposure and seeking shade. Enhance your sun protection with tightly woven, yet airy clothing. Mark this! Snow reflection can nearly double the UV radiation intensity from the Sun.
Frequently asked questions
What time of the year is the coldest in Herndon?
How cold is January in Herndon?
What is the average humidity in January in Herndon?
How much does it rain in Herndon in January?
When does it snow the most in Herndon?
How much does it snow in Herndon in January?
How many hours of daylight does Herndon have in January?
When are sunrise and sunset in January in Herndon?
What are the months with the least sunshine in Herndon?
How many hours of sunshine does Herndon have in January?
What is the month with the lowest UV index in Herndon?
What is the UV index reading in January in Herndon?
Average temperature in January
Herndon, VA
- Average high temperature in January: 39.7°F
The warmest month (with the highest average high temperature) is July (87.8°F).
The month with the lowest average high temperature is January (39.7°F).
- Average low temperature in January: 25.9°F
The month with the highest average low temperature is July (67.3°F).
The coldest month (with the lowest average low temperature) is January (25.9°F).
Average pressure in January
Herndon, 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
Herndon, VA
- Average wind speed in January: 7.2mph
The windiest month (with the highest average wind speed) is March (7.5mph).
The calmest month (with the lowest average wind speed) is August (4.7mph).
Average humidity in January
Herndon, VA
- Average humidity in January: 74%
The month with the highest relative humidity is December (78%).
The month with the lowest relative humidity is July (70%).
Average rainfall in January
Herndon, VA
- Average rainfall in January: 2.13"
The wettest month (with the highest rainfall) is August (3.78").
The driest month (with the least rainfall) is September (1.93").
Average rainfall days in January
Herndon, VA
- Average rainfall days in January: 9.3 days
The month with the highest number of rainy days is May (17.5 days).
The month with the least rainy days is January (9.3 days).
Average snowfall in January
Herndon, 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
Herndon, VA
- Average snowfall days in January: 5.1 days
The months with the highest number of snowfall days are January and February (5.1 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
Herndon, VA
- Average daylight in January: 9h and 5min
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 30min).
- Average sunshine in January: 5h and 0min
The month with the most sunshine is July (Average sunshine: 10h and 42min).
The months with the least sunshine are January, February and December (Average sunshine: 5h and 0min).
Average sunshine days in January
Herndon, VA
- Average sunshine days in January: 17.2 days
The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is July (11.8 days).
Average UV index in January
Herndon, 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
Herndon, VA
- Average cloud cover in January: 46
The month with the most cloud cover is March (Cloud cover 48).
The month with the least cloud cover is July (Cloud cover 31).
Average visibility in January
Herndon, 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).
Herndon, Virginia, USA
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