Climate and monthly weather forecast
Herndon, VA

Weather in January

January, like December, in Herndon, Virginia, is another cold winter month, with an average temperature varying between 25.9°F (-3.4°C) and 39.7°F (4.3°C). With an average high-temperature of 39.7°F (4.3°C) and an average low-temperature of 25.9°F (-3.4°C), January is the coldest month. Weather in January »

Weather in February

The last month of the winter, February, is a chilly month in Herndon, Virginia, with an average temperature varying between 43.9°F (6.6°C) and 28°F (-2.2°C). In Herndon, the average high-temperature in February is almost the same as in January - a chilly 43.9°F (6.6°C). Weather in February »

Weather in March

March, the first month of the spring in Herndon, is a cool month, with an average temperature fluctuating between 35.6°F (2°C) and 52.5°F (11.4°C). In March, the average high-temperature slightly increases from a frosty 43.9°F (6.6°C) in February to a fresh 52.5°F (11.4°C). Weather in March »

Weather in April

April in Herndon, Virginia, is a comfortable spring month, with an average temperature varying between 45.7°F (7.6°C) and 64.9°F (18.3°C). In Herndon, the average high-temperature in April rises from a cool 52.5°F (11.4°C) in March to an enjoyable 64.9°F (18.3°C). Weather in April »

Weather in May

May, the last month of the spring in Herndon, is a moderately hot month, with an average temperature varying between 55°F (12.8°C) and 75°F (23.9°C). In Herndon, the average high-temperature in May rises from a comfortable 64.9°F (18.3°C) in April to a moderately hot 75°F (23.9°C). Weather in May »

Weather in June

June, the first month of the summer in Herndon, is still a warm month, with an average temperature ranging between max 82.8°F (28.2°C) and min 62.4°F (16.9°C). In Herndon, Virginia, the average high-temperature in June marginally rises from 75°F (23.9°C) in May to a still warm 82.8°F (28.2°C). Weather in June »

Weather in July

July is a hot summer month in Herndon, Virginia, with an average temperature fluctuating between 87.8°F (31°C) and 67.3°F (19.6°C). July is the warmest month, with an average high-temperature of 87.8°F (31°C) and an average low-temperature of 67.3°F (19.6°C). The average heat index in July is calculated to be a very hot 100.4°F (38°C). Weather in July »

Weather in August

The last month of the summer, August, is also a moderately hot month in Herndon, Virginia, with temperature in the range of an average high of 85.6°F (29.8°C) and an average low of 66°F (18.9°C). In Herndon, the average high-temperature in August is almost the same as in July - a warm 85.6°F (29.8°C). Weather in August »

Weather in September

The first month of the autumn, September, is still a warm month in Herndon, Virginia, with an average temperature ranging between min 59.7°F (15.4°C) and max 78.3°F (25.7°C). In Herndon, the average high-temperature in September slightly decreases from 85.6°F (29.8°C) in August to a still moderately hot 78.3°F (25.7°C). Weather in September »

Weather in October

October, like September, in Herndon, Virginia, is another enjoyable autumn month, with an average temperature ranging between min 49.1°F (9.5°C) and max 66°F (18.9°C). In October, the average high-temperature decreases from a moderately hot 78.3°F (25.7°C) in September to a comfortable 66°F (18.9°C). Weather in October »

Weather in November

The last month of the autumn, November, is also a fresh month in Herndon, Virginia, with an average temperature ranging between min 37.8°F (3.2°C) and max 53.6°F (12°C). In November, the average high-temperature decreases from a comfortable 66°F (18.9°C) in October to a cool 53.6°F (12°C). Weather in November »

Weather in December

December, the first month of the winter in Herndon, is still a chilly month, with an average temperature varying between 45.1°F (7.3°C) and 32°F (0°C). In December, the average high-temperature marginally drops from a fresh 53.6°F (12°C) in November to a frosty 45.1°F (7.3°C). Weather in December »
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FAQ

What is the coldest month in Herndon?

The coldest month is January, with an average high-temperature of 39.7°F (4.3°C) and an average low-temperature of 25.9°F (-3.4°C).

How much does it rain in Herndon?

In Herndon, Virginia, during the entire year, the rain falls for 158.1 days and collects up to 31.46" (799mm) of precipitation.

When does it snow in Herndon?

January through April, November and December are months with snowfall.

What is the snowiest month in Herndon?

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.

How much does it snow in Herndon?

Throughout the year, in Herndon, Virginia, there are 16.7 snowfall days, and 12.28" (312mm) of snow is accumulated.

What is the month with the least sunshine in Herndon?

The months with the least sunshine in Herndon, Virginia, are January, February and December, with an average of 5h of sunshine.

When is the lowest UV index in Herndon?

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

When is Daylight Saving Time (DST) in Herndon?

On Sunday, March 12. 2023, at 2:00 am, Daylight Saving Time starts in Herndon, and the time zone changes from EST to EDT. Daylight Saving Time ends Sunday, November 5. 2023, at 2:00 am, and the time zone reverts from EDT to EST.

When it does not snow in Herndon?

In Herndon, snow does not fall in May through October.

What is the month with the highest UV index in Herndon?

May through August, with an average maximum UV index of 6, are months with the highest UV index in Herndon, Virginia.

When are the longest days in Herndon?

June has the longest days of the year in Herndon, with an average of 14h and 52min of daylight.

What is the warmest month in Herndon?

The warmest month in Herndon, Virginia, is July, with an average high-temperature of 87.8°F (31°C) and an average low-temperature of 67.3°F (19.6°C).

What is the least humid month in Herndon?

July is the least humid month in Herndon, Virginia, with an average relative humidity of 70%.

What month has the most sunshine in Herndon?

The month with the most sunshine is July, with an average of 10.7h of sunshine.

What is the rainiest month in Herndon?

August is the month with the most rainfall in Herndon, Virginia. Rain falls for 16.7 days and accumulates 3.78" (96mm) of precipitation.

What is the driest month in Herndon?

The month with the least rainfall is September, when the rain falls for 12.6 days and typically collects 1.93" (49mm) of precipitation.

What is the most humid month in Herndon?

The most humid month is December, with an average relative humidity of 78%.

What is the month with the shortest days in Herndon?

The month with the shortest days in Herndon is December, with an average of 9h and 29min of daylight.

Average pressure
Herndon, VA

Average pressure - Herndon, VA

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
Herndon, VA

Average wind speed - Herndon, VA

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).

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Average rainfall
Herndon, VA

Average rainfall - Herndon, VA

The wettest month (with the highest rainfall) is August (3.78").
The driest month (with the least rainfall) is September (1.93").

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Average rainfall days
Herndon, VA

Average rainfall days - Herndon, VA

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).

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Average snowfall
Herndon, VA

Average snowfall - Herndon, VA

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
Herndon, VA

Average snowfall days - Herndon, VA

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).

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Average daylight / Average sunshine
Herndon, VA

Average daylight / Average sunshine - Herndon, VA

The month with the longest days is June (Average daylight: 14h and 52min).
The month with the shortest days is December (Average daylight: 9h and 29min).

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).

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Average sunshine days
Herndon, VA

Average sunshine days - Herndon, VA

The month with the most sunshine days is November (19.5 days).
The month with the least sunshine days is July (11.8 days).

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Average UV index
Herndon, VA

Average UV index - Herndon, VA

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 visibility
Herndon, VA

Average visibility - Herndon, VA

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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