Climate and monthly weather forecast
Jefferson, CO

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Weather in January

January, like December, is another subzero cold winter month in Jefferson, Colorado, with an average temperature varying between 22.5°F (-5.3°C) and 0.7°F (-17.4°C). The dawn of January sees an average high-temperature of a still freezing cold 22.5°F (-5.3°C), subtly contrasting with December's 21.2°F (-6°C). Weather in January »

Weather in February

February, the last month of the winter in Jefferson, is also a subzero cold month, with temperature in the range of an average high of 22.5°F (-5.3°C) and an average low of 1.8°F (-16.8°C). As January turns into February, the average high-temperatures rest at a still freezing cold 22.5°F (-5.3°C), without variation from the prior month. Weather in February »

Weather in March

The first month of the spring, March, is also a subzero cold month in Jefferson, Colorado, with temperature in the range of an average high of 28.8°F (-1.8°C) and an average low of 8.1°F (-13.3°C). The start of March is characterized by a subtle increase in the average high-temperature, transitioning from a freezing cold 22.5°F (-5.3°C) in February to a still subzero cold 28.8°F (-1.8°C). Weather in March »

Weather in April

April in Jefferson, Colorado, is a cold spring month, with an average temperature ranging between max 33.6°F (0.9°C) and min 13.5°F (-10.3°C). The transition into April shows a subtle variation to a cold 33.6°F (0.9°C) from March's 28.8°F (-1.8°C) in the average high-temperature. Weather in April »

Weather in May

The last month of the spring, May, is a frosty month in Jefferson, Colorado, with an average temperature ranging between min 23.4°F (-4.8°C) and max 45.5°F (7.5°C). Jefferson, Colorado, sees a rise in temperature during May, with average high-temperatures transitioning from a cold 33.6°F (0.9°C) in April to a chilly 45.5°F (7.5°C). Weather in May »

Weather in June

The first month of the summer, June, is a comfortable month in Jefferson, Colorado, with an average temperature ranging between max 61.3°F (16.3°C) and min 35.1°F (1.7°C). Jefferson's June weather is characterized by a distinct upsurge in high-temperatures, soaring from May's chilly 45.5°F (7.5°C) to a refreshing 61.3°F (16.3°C). Weather in June »

Weather in July

July, the same as June, is another enjoyable summer month in Jefferson, Colorado, with temperature in the range of an average low of 40.1°F (4.5°C) and an average high of 65.8°F (18.8°C). July, with average temperatures reaching a high of 65.8°F (18.8°C) and a low of 40.1°F (4.5°C), is the warmest month. Weather in July »

Weather in August

The last month of the summer, August, is another refreshing month in Jefferson, Colorado, with an average temperature fluctuating between 63.7°F (17.6°C) and 37.9°F (3.3°C). Transitioning into August, Jefferson experiences an average high-temperature of a still comfortable 63.7°F (17.6°C), marking a minor shift from the preceding month. Weather in August »

Weather in September

The first month of the autumn, September, is still a mild month in Jefferson, Colorado, with an average temperature varying between 57.6°F (14.2°C) and 33.4°F (0.8°C). The arrival of September corresponds with a minor reduction in the average high-temperature, down from August's refreshing 63.7°F (17.6°C) to a moderate 57.6°F (14.2°C). Weather in September »

Weather in October

October, the same as September, in Jefferson, Colorado, is another chilly autumn month, with an average temperature ranging between max 43.3°F (6.3°C) and min 22.3°F (-5.4°C). As September transitions into October, Jefferson sees a drop in the average high-temperature, transitioning from a moderate 57.6°F (14.2°C) to a frosty 43.3°F (6.3°C). Weather in October »

Weather in November

November, the last month of the autumn in Jefferson, is another freezing cold month, with an average temperature fluctuating between 31.1°F (-0.5°C) and 10.9°F (-11.7°C). The shift from October to November involves a decrease in the average high-temperature, from a chilly 43.3°F (6.3°C) to a subzero cold 31.1°F (-0.5°C). Weather in November »

Weather in December

The first month of the winter, December, is also a subzero cold month in Jefferson, Colorado, with temperature in the range of an average low of 0.7°F (-17.4°C) and an average high of 21.2°F (-6°C). The coldest period tends to be December, when average temperatures fluctuate between a high of 21.2°F (-6°C) and a low of 0.7°F (-17.4°C). Weather in December »
Updated: Jul 12, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How many days does it rain?

In Jefferson, during the entire year, the rain falls for 110.4 days and collects up to 24.09" (612mm) of precipitation.

When does it snow?

January through December are months with snowfall.

How many days does it snow?

In Jefferson, during the entire year, snow falls for 158 days and aggregates up to 118.82" (3018mm) of snow.

What is the most humid month?

The most humid month is February, with an average relative humidity of 89%.

What is the month with the least sunshine?

February has the least sunshine of the year, with an average of 5.2h of sunshine.

What is the month with the lowest UV index?

The months with the lowest UV index are February and December, with an average maximum UV index of 1.

When is Daylight Saving Time (DST)?

On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts, and the time zone changes from MST to MDT. Daylight Saving Time ends Sunday, November 3. 2024, at 2:00 am, and the time zone reverts from MDT to MST.

When does it snow the most?

May is the month with the most snowfall. Snow falls for 19 days and accumulates 19.69" (500mm) of snow.

What are the months with the highest UV index?

May through August, with an average maximum UV index of 3, are months with the highest UV index.

What is the least humid month?

The least humid month is June, with an average relative humidity of 54%.

When are the longest days?

With an average of 14h and 54min of daylight, June has the longest days of the year.

What month has the most sunshine?

The month with the most sunshine is June, with an average of 11.4h of sunshine.

What is the warmest month?

The warmest month is July, with an average high-temperature of 65.8°F (18.8°C) and an average low-temperature of 40.1°F (4.5°C).

What is the rainiest month in Jefferson?

The month with the most rainfall is July, when the rain falls for 22.8 days and typically aggregates up to 3.35" (85mm) of precipitation.

When it does not snow?

July is the month with the least snowfall. Snow falls for 1.3 days and accumulates 0.24" (6mm) of snow.

What is the driest month?

November is the month with the least rainfall in Jefferson. Rain falls for 2.8 days and accumulates 1.14" (29mm) of precipitation.

What part of the year is the coldest?

Jefferson's coldest weather arrives in December, when temperatures average a high of 21.2°F (-6°C) and a low of 0.7°F (-17.4°C).

What is the month with the shortest days?

December has the shortest days of the year, with an average of 9h and 24min of daylight.

Average temperature
Jefferson, CO

Average temperature - Jefferson, CO

The warmest month (with the highest average high temperature) is July (65.8°F).
The month with the lowest average high temperature is December (21.2°F).

The month with the highest average low temperature is July (40.1°F).
The coldest months (with the lowest average low temperature) are January and December (0.7°F).

Average pressure
Jefferson, CO

Average pressure - Jefferson, CO

The month with the highest atmospheric pressure is January (30.19"Hg).
The months with the lowest atmospheric pressure are April and May (29.94"Hg).

Average wind speed
Jefferson, CO

Average wind speed - Jefferson, CO

The windiest month (with the highest average wind speed) is February (7mph).
The calmest month (with the lowest average wind speed) is August (4.8mph).

Average humidity
Jefferson, CO

Average humidity - Jefferson, CO

The month with the highest relative humidity is February (89%).
The month with the lowest relative humidity is June (54%).

Average rainfall
Jefferson, CO

Average rainfall - Jefferson, CO

The wettest month (with the highest rainfall) is July (3.35").
The driest month (with the least rainfall) is November (1.14").

Average rainfall days
Jefferson, CO

Average rainfall days - Jefferson, CO

The month with the highest number of rainy days is July (22.8 days).
The month with the least rainy days is November (2.8 days).

Average snowfall
Jefferson, CO

Average snowfall - Jefferson, CO

The month with the highest snowfall is May (19.69").
The month with the least snowfall is July (0.24").

Average snowfall days
Jefferson, CO

Average snowfall days - Jefferson, CO

The month with the highest number of snowfall days is April (22.8 days).
The month with the least snowfall days is July (1.3 days).

Average daylight / Average sunshine
Jefferson, CO

Average daylight / Average sunshine - Jefferson, CO

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 24min).

The month with the most sunshine is June (Average sunshine: 11h and 24min).
The month with the least sunshine is February (Average sunshine: 5h and 12min).

Average sunshine days
Jefferson, CO

Average sunshine days - Jefferson, CO

The month with the most sunshine days is November (18.5 days).
The month with the least sunshine days is July (5.8 days).

Average UV index
Jefferson, CO

Average UV index - Jefferson, CO

The months with the highest UV index are May, June, July and August (UV index 3).
The months with the lowest UV index are February and December (UV index 1).

Average visibility
Jefferson, CO

Average visibility - Jefferson, CO

The months with the highest visibility are June, July, August, September and October (6mi).
The months with the lowest visibility are January, February, March, April and December (4mi).

Jefferson, Colorado, USA

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