January weather forecast
Boulder, CO

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The old building of the University of Colorado in Boulder, Colorado
The old building of the University of Colorado in Boulder, Colorado

Weather in January

In Boulder, Colorado, January brings the year's chilliest weather. The month commences with colder average temperatures, reaching a high approximately of 36.7°F (2.6°C) and plummeting to lows approximately of 19°F (-7.2°C). Peaks of precipitation with snowfall reaching 2.87" (73mm) also characterize the month. A contrast arises in February, when temperatures exhibit a slight increase, making the weather slightly less biting. Prospect of outdoor pursuits in January ought to accommodate warmer clothing and snow gear.

Temperature

During January, the average high-temperature is a still icy 36.7°F (2.6°C), maintaining a close resemblance to that of the preceding month. An average minimum temperature of 19°F (-7.2°C) marks the month of January.

Humidity

The average relative humidity in January in Boulder is 68%.

Rainfall

The month with the least rainfall is January, when the rain falls for 4.3 days and typically collects 0.39" (10mm) of precipitation.

Snowfall

Months with snowfall in Boulder are January through May, October through December. In Boulder, during January, snow falls for 6.3 days and regularly aggregates up to 2.87" (73mm) of snow. Throughout the year, in Boulder, there are 44.8 snowfall days, and 37.01" (940mm) of snow is accumulated.

Daylight

The average length of the day in January in Boulder is 9h and 43min.
On the first day of the month, sunrise is at 7:22 am and sunset at 4:46 pm. On the last day of January, sunrise is at 7:10 am and sunset at 5:18 pm MST.

Sunshine

In Boulder, the average sunshine in January is 6.9h.

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 estimate of 2, and below, represents a minimal health hazard from exposure to the Sun's UV radiation for ordinary individuals.
Note: In January, a regular UV index of 2 translates into these guidelines:
While extended sun exposure does not significantly affect most people, those with sensitive skin, children, and infants should always be protected. The Sun's most harmful UV rays are emitted around midday; avoid staying outdoors for long during this time. Using UVA and UVB-protective sunglasses and sun-protective clothing is effective against UV radiation. Consider this! The reflection from snow can almost double the intensity of the Sun's UV radiation.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

How cold is it in Boulder in January?

In January, in Boulder, the average high-temperature is 36.7°F (2.6°C), and the average low-temperature is 19°F (-7.2°C).

What is the average humidity in January in Boulder?

The average relative humidity in January in Boulder, Colorado, is 68%.

What is the driest month in Boulder?

January is the month with the least rainfall in Boulder, Colorado. Rain falls for 4.3 days and accumulates 0.39" (10mm) of precipitation.

How much does it rain in Boulder in January?

In Boulder, Colorado, in January, it is raining for 4.3 days, with typically 0.39" (10mm) of accumulated precipitation.

How much does it snow in Boulder in January?

In Boulder, during January, snow falls for 6.3 days and regularly aggregates up to 2.87" (73mm) of snow.

What is the average length of the day in January in Boulder?

In Boulder, Colorado, the average day length in January is 9h and 43min.

What time are sunrise and sunset in January in Boulder?

In January, on the first day of the month, sunrise is at 7:22 am and sunset at 4:46 pm. On the last day of the month, in Boulder, sunrise is at 7:10 am and sunset at 5:18 pm MST.

How many hours of sunshine does Boulder have in January?

The average sunshine duration in January is 6.9h.

When is the lowest UV index in Boulder?

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

How high is the UV index in January in Boulder?

In January, the average daily maximum UV index in Boulder is 2. A UV Index reading of 2, and below, represents a low health threat from exposure to the Sun's UV radiation.
Average humidity
Average rainfall days
Average snowfall days
Average daylight
Average sunshine
Average sunshine days
Average UV index
Average cloud cover
Average visibility

Average temperature in January
Boulder, CO

Average temperature in January - Boulder, CO
  • Average high temperature in January: 36.7°F

The warmest month (with the highest average high temperature) is July (80.4°F).
The month with the lowest average high temperature is December (35.2°F).

  • Average low temperature in January: 19°F

The month with the highest average low temperature is July (55.2°F).
The coldest month (with the lowest average low temperature) is February (18°F).

Average pressure in January
Boulder, CO

Average pressure in January - Boulder, CO
  • Average pressure in January: 30.15"Hg

The month with the highest atmospheric pressure is January (30.15"Hg).
The months with the lowest atmospheric pressure are April, May and June (29.92"Hg).

Average wind speed in January
Boulder, CO

Average wind speed in January - Boulder, CO
  • Average wind speed in January: 7.3mph

The windiest month (with the highest average wind speed) is January (7.3mph).
The calmest months (with the lowest average wind speed) are May, July, August and September (5.7mph).

Average humidity in January
Boulder, CO

Average humidity in January - Boulder, CO
  • Average humidity in January: 68%

The month with the highest relative humidity is February (70%).
The months with the lowest relative humidity are June, August and September (45%).

Average rainfall in January
Boulder, CO

Average rainfall in January - Boulder, CO
  • Average rainfall in January: 0.39"

The wettest month (with the highest rainfall) is May (2.48").
The driest month (with the least rainfall) is January (0.39").

Average rainfall days in January
Boulder, CO

Average rainfall days in January - Boulder, CO
  • Average rainfall days in January: 4.3 days

The month with the highest number of rainy days is July (17.8 days).
The month with the least rainy days is November (3.3 days).

Average snowfall in January
Boulder, CO

Average snowfall in January - Boulder, CO
  • Average snowfall in January: 2.87"

The month with the highest snowfall is April (7.76").
The months with the least snowfall are June, July, August and September (0").

Average snowfall days in January
Boulder, CO

Average snowfall days in January - Boulder, CO
  • Average snowfall days in January: 6.3 days

The month with the highest number of snowfall days is February (10.3 days).
The months with the least snowfall days are June, July and August (0 days).

Average daylight in January /
Average sunshine in January
Boulder, CO

Average daylight in January / Average sunshine in January - Boulder, CO
  • 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 24min).

  • Average sunshine in January: 6h and 5min

The months with the most sunshine are June and July (Average sunshine: 11h and 42min).
The month with the least sunshine is February (Average sunshine: 6h and 36min).

Average sunshine days in January
Boulder, CO

Average sunshine days in January - Boulder, CO
  • Average sunshine days in January: 22.2 days

The month with the most sunshine days is January (22.2 days).
The month with the least sunshine days is July (9.9 days).

Average UV index in January
Boulder, CO

Average UV index in January - Boulder, CO
  • Average UV index in January: 2

The months with the highest UV index are June, July and August (UV index 5).
The months with the lowest UV index are January, February, November and December (UV index 2).

Average cloud cover in January
Boulder, CO

Average cloud cover in January - Boulder, CO
  • Average cloud cover in January: 22

The months with the most cloud cover are April and May (Cloud cover 28).
The month with the least cloud cover is September (Cloud cover 16).

Average visibility in January
Boulder, CO

Average visibility in January - Boulder, CO
  • Average visibility in January: 6mi

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

Boulder, Colorado, USA

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