Monthly weather forecast and climate
Longmont, CO

Weather in January

January, like December, in Longmont, Colorado, is a wintry winter month, with average temperature varying between 21.2°F (-6°C) and 40.1°F (4.5°C). In Longmont, the average high-temperature in January is relatively the same as in December - a still wintry 40.1°F (4.5°C). Weather in January »

Weather in February

February, the last month of the winter, in Longmont, is also a wintry month, with average temperature fluctuating between 40.3°F (4.6°C) and 20.8°F (-6.2°C). In Longmont, the average high-temperature is practically the same as in January - a still cold 40.3°F (4.6°C). Weather in February »

Weather in March

The first month of the spring, March, is a fresh month in Longmont, Colorado, with average temperature ranging between min 29.7°F (-1.3°C) and max 51.4°F (10.8°C). In March, the average high-temperature increases, from a wintry 40.3°F (4.6°C) in February, to a cool 51.4°F (10.8°C). Weather in March »

Weather in April

April in Longmont, Colorado, is a moderate spring month, with average temperature varying between 34.3°F (1.3°C) and 57.7°F (14.3°C). In Longmont, the average high-temperature in April slightly increases, from a cool 51.4°F (10.8°C) in March, to a mild 57.7°F (14.3°C). Weather in April »

Weather in May

The last month of the spring, May, is a comfortable month in Longmont, Colorado, with average temperature varying between 66.4°F (19.1°C) and 42.6°F (5.9°C). In Longmont, the average high-temperature slightly increases, from a moderate 57.7°F (14.3°C) in April, to a comfortable 66.4°F (19.1°C). Weather in May »

Weather in June

The first month of the summer, June, is a warm month in Longmont, Colorado, with average temperature ranging between max 81.1°F (27.3°C) and min 54.3°F (12.4°C). In Longmont, the average high-temperature in June increases considerably, from an enjoyable 66.4°F (19.1°C) in May, to a warm 81.1°F (27.3°C). Weather in June »

Weather in July

July, the same as June, is a moderately hot summer month in Longmont, Colorado, with average temperature varying between 85.6°F (29.8°C) and 59.2°F (15.1°C). The warmest month is July, with an average high-temperature of 85.6°F (29.8°C) and an average low-temperature of 59.2°F (15.1°C). In July, the average heat index is evaluated at a tropical 86.2°F (30.1°C). Weather in July »

Weather in August

August, the last month of the summer, in Longmont, is also a moderately hot month, with average temperature ranging between max 84.7°F (29.3°C) and min 57.4°F (14.1°C). In Longmont, the average high-temperature in August is almost the same as in July - a still moderately hot 84.7°F (29.3°C). Weather in August »

Weather in September

September, the first month of the autumn, in Longmont, is still a warm month, with temperature in the range of an average high of 77.2°F (25.1°C) and an average low of 51.1°F (10.6°C). In Longmont, the average high-temperature in September marginally drops, from a warm 84.7°F (29.3°C) in August, to a still moderately hot 77.2°F (25.1°C). Weather in September »

Weather in October

October, the same as September, is another comfortable autumn month in Longmont, Colorado, with average temperature ranging between max 61.5°F (16.4°C) and min 38.3°F (3.5°C). In October, the average high-temperature declines considerably, from a warm 77.2°F (25.1°C) in September, to a comfortable 61.5°F (16.4°C). Weather in October »

Weather in November

The last month of the autumn, November, is another cool month in Longmont, Colorado, with temperature in the range of an average high of 50.4°F (10.2°C) and an average low of 29.1°F (-1.6°C). In November, the average high-temperature drops, from a comfortable 61.5°F (16.4°C) in October, to a fresh 50.4°F (10.2°C). Weather in November »

Weather in December

The first month of the winter, December, is also a wintry month in Longmont, Colorado, with average temperature varying between 19.9°F (-6.7°C) and 39°F (3.9°C). December is the coldest month, with an average high-temperature of 39°F (3.9°C) and an average low-temperature of 19.9°F (-6.7°C). Weather in December »
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FAQ

How many days does it rain in Longmont?

Throughout the year, there are 105.4 rainfall days, and 10.43" (265mm) of precipitation is accumulated.

What is the driest month in Longmont?

January is the month with the least rainfall. Rain falls for 3.5 days and accumulates 0.35" (9mm) of precipitation.

When does it snow in Longmont?

Months with snowfall in Longmont, Colorado, are January through May, October through December.

How much does it snow in Longmont?

Throughout the year, in Longmont, there are 37.1 snowfall days, and 26.73" (679mm) of snow is accumulated.

When is the lowest UV index in Longmont?

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

What is the most humid month in Longmont?

February is the most humid month, with an average relative humidity of 66%.

What is the month with the least sunshine in Longmont?

February has the least sunshine of the year in Longmont, with an average of 6.8h of sunshine.

What is the rainiest month in Longmont?

May is the month with the most rainfall. Rain falls for 15 days and accumulates 1.69" (43mm) of precipitation.

When it does not snow in Longmont?

June through September are months without snowfall in Longmont.

When are the longest days in Longmont?

June has the longest days of the year, with an average of 15h of daylight.

What month has the most sunshine in Longmont?

June has the most sunshine of the year in Longmont, Colorado, with an average of 11.9h of sunshine.

What is the warmest month in Longmont?

With an average high-temperature of 85.6°F (29.8°C) and an average low-temperature of 59.2°F (15.1°C), July is the warmest month.

When is the highest UV index in Longmont?

July and August, with an average maximum UV index of 6, are months with the highest UV index in Longmont, Colorado.

What is the least humid month in Longmont?

With an average relative humidity of 42%, August is the least humid month in Longmont.

What is the snowiest month in Longmont?

November is the month with the most snowfall in Longmont, Colorado. Snow falls for 5.4 days and accumulates 4.41" (112mm) of snow.

What is the coldest month in Longmont?

December is the coldest month, with an average high-temperature of 39°F (3.9°C) and an average low-temperature of 19.9°F (-6.7°C).

What is the month with the shortest days in Longmont?

December has the shortest days of the year, with an average of 9.4h of daylight.

Average temperature
Longmont, CO

Average temperature - Longmont, CO

The warmest month (with the highest average high temperature) is July (85.6°F).
The month with the lowest average high temperature is December (39°F).

The month with the highest average low temperature is July (59.2°F).
The coldest month (with the lowest average low temperature) is December (19.9°F).

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Average pressure
Longmont, CO

Average pressure - Longmont, CO

The month with the highest atmospheric pressure is January (30.15").
Months with the lowest atmospheric pressure are April and June (29.91").

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Average wind speed
Longmont, CO

Average wind speed - Longmont, CO

The windiest months (with the highest average wind speed) are March and April (6.6mph).
The calmest months (with the lowest average wind speed) are August and September (5.6mph).

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Average rainfall
Longmont, CO

Average rainfall - Longmont, CO

The wettest month (with the highest rainfall) is May (1.69").
The driest month (with the least rainfall) is January (0.35").

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Average rainfall days
Longmont, CO

Average rainfall days - Longmont, CO

The month with the highest number of rainy days is July (16 days).
The month with the least rainy days is January (3.5 days).

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Average snowfall
Longmont, CO

Average snowfall - Longmont, CO

The month with the highest snowfall is November (4.41").
Months with the least snowfall are June, July, August and September (0").

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Average snowfall days
Longmont, CO

Average snowfall days - Longmont, CO

The month with the highest number of snowfall days is February (7.7 days).
Months with the least snowfall days are June, July and August (0 days).

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Average daylight / Average sunshine
Longmont, CO

Average daylight / Average sunshine - Longmont, CO

The month with the longest days is June (Average daylight: 15h).
The month with the shortest days is December (Average daylight: 9.4h).

The month with the most sunshine is June (Average sunshine: 11.9h).
The month with the least sunshine is February (Average sunshine: 6.8h).

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Average sunshine days
Longmont, CO

Average sunshine days - Longmont, CO

The month with the most sunshine days is January (23.4 days).
The month with the least sunshine days is July (9.3 days).

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Average UV index
Longmont, CO

Average UV index - Longmont, CO

Months with the highest UV index are July and August (UV index 6).
Months with the lowest UV index are January, February, November and December (UV index 2).

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Average visibility
Longmont, CO

Average visibility - Longmont, CO

Months with the highest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).
Months with the lowest visibility are January, February, March, April, May, June, July, August, September, October, November and December (6mi).

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