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, noted for its average high-temperature of 32.9°F (0.5°C) and an average low-temperature of 20.1°F (-6.6°C), is considered the coldest month.Humidity
The average relative humidity in January is 79%.Rainfall
In Herndon, during January, the rain falls for 9.3 days and regularly aggregates up to 2.2" (56mm) of precipitation. In Herndon, during the entire year, the rain falls for 165.3 days and collects up to 30.55" (776mm) of precipitation.Snowfall
Months with snowfall in Herndon are January through May, October through December. In January, it is snowing for 11.3 days. Throughout January, 4.41" (112mm) of snow is accumulated. Throughout the year, there are 38.1 snowfall days, and 17.68" (449mm) of snow is accumulated.Daylight
The average length of the day in January in Herndon is 9h and 39min.On the first day of the month, sunrise is at 7:31 am and sunset at 4:50 pm. On the last day of January, in Herndon, Pennsylvania, sunrise is at 7:18 am and sunset at 5:23 pm EST.
Sunshine
In Herndon, the average sunshine in January is 4.3h.UV index
The months with the lowest UV index are January through March, November and December, with an average maximum UV index of 2. A UV Index reading of 2, and below, represents a low threat to health from exposure to the Sun's UV rays for average individuals.Note: A daily maximum UV index of 2 in January translates into the following instructions:
Although the majority can endure up to an hour in the sun without burns, children always require sun protection. The most potent solar radiation is around mid-day, so one should minimize exposure to direct sunlight during this period. A wide-brimmed hat provides unparalleled sun protection for sensitive areas like the eyes, ears, and neck. Take to heart! Snow reflection can almost magnify the Sun's UV radiation twofold.
Frequently asked questions
What month is the coldest in Herndon?
How cold is it in Herndon in January?
What is the average humidity in January in Herndon?
How much does it rain in Herndon in January?
How many days does it snow in January in Herndon?
What is the average length of the day in January in Herndon?
When is the sunrise / sunset in January in Herndon?
How long on average sun shines in January in Herndon?
What are the months with the lowest UV index in Herndon?
What is the UV index reading in January in Herndon?
Average temperature in January
Herndon, PA
- Average high temperature in January: 32.9°F
The warmest month (with the highest average high temperature) is July (82.4°F).
The month with the lowest average high temperature is January (32.9°F).
- Average low temperature in January: 20.1°F
The month with the highest average low temperature is July (61.2°F).
The coldest month (with the lowest average low temperature) is January (20.1°F).
Average pressure in January
Herndon, PA
- Average pressure in January: 30.09"Hg
The month with the highest atmospheric pressure is November (30.13"Hg).
The month with the lowest atmospheric pressure is June (29.94"Hg).
Average wind speed in January
Herndon, PA
- Average wind speed in January: 7.5mph
The windiest months (with the highest average wind speed) are March and April (7.8mph).
The calmest month (with the lowest average wind speed) is August (4.5mph).
Average humidity in January
Herndon, PA
- Average humidity in January: 79%
The month with the highest relative humidity is February (82%).
The month with the lowest relative humidity is April (76%).
Average rainfall in January
Herndon, PA
- Average rainfall in January: 2.2"
The wettest month (with the highest rainfall) is May (3.35").
The driest months (with the least rainfall) are February and November (2.09").
Average rainfall days in January
Herndon, PA
- Average rainfall days in January: 9.3 days
The month with the highest number of rainy days is May (18.4 days).
The month with the least rainy days is February (9 days).
Average snowfall in January
Herndon, PA
- Average snowfall in January: 4.41"
The month with the highest snowfall is February (5.67").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days in January
Herndon, PA
- Average snowfall days in January: 11.3 days
The month with the highest number of snowfall days is January (11.3 days).
The months with the least snowfall days are June, July, August and September (0 days).
Average daylight in January /
Average sunshine in January
Herndon, PA
- Average daylight in January: 9h and 4min
The month with the longest days is June (Average daylight: 15h and 0min).
The month with the shortest days is December (Average daylight: 9h and 18min).
- Average sunshine in January: 4h and 2min
The month with the most sunshine is July (Average sunshine: 10h and 24min).
The month with the least sunshine is February (Average sunshine: 4h and 12min).
Average sunshine days in January
Herndon, PA
- Average sunshine days in January: 13.9 days
The month with the most sunshine days is November (16.4 days).
The month with the least sunshine days is May (9.9 days).
Average UV index in January
Herndon, PA
- Average UV index in January: 2
The months with the highest UV index are June and July (UV index 6).
The months with the lowest UV index are January, February, March, November and December (UV index 2).
Average cloud cover in January
Herndon, PA
- Average cloud cover in January: 53
The month with the most cloud cover is February (Cloud cover 54).
The month with the least cloud cover is July (Cloud cover 32).
Average visibility in January
Herndon, PA
- Average visibility in January: 5mi
The months with the highest visibility are March, April, June, July and November (6mi).
The months with the lowest visibility are January, February, May, August, September, October and December (5mi).
Herndon, Pennsylvania, USA
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