Climate and monthly weather forecastLongmont, CO
Climate and monthly weather forecast
The climate of Longmont
Longmont, situated in Colorado, USA, experiences a predominate Mid-latitude steppe climate as per the Köppen climate classification (BSk). This climate type indicates that Longmont is characterized by hot, sometimes extremely hot summers and cold, sometimes very cold and arid winters.An overview of climatic parameters reveals a varied temperature span. The year usually starts and ends with the lower temperatures (from 21.2°F (-6°C) to 40.1°F (4.5°C) in January, and from 19.9°F (-6.7°C) to 39°F (3.9°C) in December). A steady rise in temperature occurs from February (from 20.8°F (-6.2°C) to 40.3°F (4.6°C)) to July, marking the peak of summer, when the minimum and maximum temperatures are 59.2°F (15.1°C) and 85.6°F (29.8°C), respectively. Subsequently, the temperature gradually declines towards the end of the year.
Rainfall patterns in Longmont are not constant throughout the year. The city experiences the least rainfall in January and December with 0.35" (9mm) and 0.39" (10mm), respectively. The maximum rainfall occurs in May, recording an average of 1.69" (43mm). By contrast, Snowfall is observed from January to April and again from October to December, with January recording the highest snowfall at 2.64" (67mm). Regarding general atmospheric conditions, relative humidity ranges between 42% to 66%, and air pressure varies minimally around a mean of 30" (762mm).
The best time to visit Longmont
Visitors who enjoy mild temperatures with moderate rainfall can choose to visit Longmont between May and June when the average high temperature varies from 66.4°F (19.1°C) to 81.1°F (27.3°C), rainfall hovers around 1.69" (43mm) to 0.94" (24mm), and daylight hours are abundantly available between 14.4 hours to 15 hours per day. Sunshine hours also peak in June, offering 11.9 hours of sunshine per day, thus making it a favorable period for out-of-door activities.The worst time to visit Longmont
Conversely, for those sensitive to cold, the period from December to February may prove to be uncomfortable. During this period, the lowest temperature drops to 19.9°F (-6.7°C) and the maximum temperature struggles to reach 40.3°F (4.6°C). This period also records the highest snowfall, from 2.64" (67mm) in January to 3.9" (99mm) in February, which could pose challenges to travel.Spring weather in Longmont
Spring in Longmont, occurring from March to May, brings a mixed bag of weather conditions. The temperature during this season ranges from 29.7°F (-1.3°C) to 66.4°F (19.1°C). An ever-increasing amount of rainfall is observed as Spring progresses, with rainfall increasing from 0.83" (21mm) in March to 1.69" (43mm) in May.Summer weather in Longmont
Summer, which spans from June to August, sees the temperature reaching from 54.3°F (12.4°C) to 85.6°F (29.8°C). These months are relatively dry, with an average rainfall from 0.94" (24mm) to 1.54" (39mm). However, the month of June is the period of maximum sunlight with an average of 15 daylight hours and 11.9 sunshine hours per day.Autumn weather in Longmont
Autumn weather, which spreads from September to November, returns to cooler temperatures, with the thermometer dipping from 51.1°F (10.6°C) in September to 29.1°F (-1.6°C) by the end of November. Rainfall reduces in this period to an average of 0.63" (16mm) in November, and daylight hours come down to 10 hours per day.Winter weather in Longmont
Winter, from December to February, is marked by a sharp drop in temperature leading to cold to further colder weather. December witnesses a range in temperature from 19.9°F (-6.7°C) to 39°F (3.9°C), gradually increasing to a range from 20.8°F (-6.2°C) to 40.3°F (4.6°C) in February. During this period, Longmont experiences significant snowfall, peaking at 3.9" (99mm) in February, and minimum daylight hours averaging 9.7 in December to 10.7 in February.Weather in January
Transitioning from the cold end of the previous year, January in Longmont, Colorado, continues to experience similarly frigid conditions. With an average high temperature of 40.1°F (4.5°C) and a chilly low of 21.2°F (-6°C), Longmont embraces the warmth of winter wear. Weather in January »Weather in February
Rolling into February, Longmont still retains its cold weather, though not as intense as its predecessor and successor. A slightly higher snowfall amount of 3.9" (99mm) is notable during the month, spread across an average of 7.7 snowy days. Weather in February »Weather in March
March marks the onset of spring in Longmont, with the weather transitioning from the chilly tones of winter to more temperate conditions. However, the city still experiences an occasional dusting of snow, though not as significant as the preceding months. Weather in March »Weather in April
In April, Longmont experiences a noticeable increase in temperatures, symbolizing the true commencement of the spring season. While rare, the month is not devoid of white powder with records of 4.29" (109mm) of snow falling over an average of 3.3 days. Weather in April »Weather in May
May is a clear departure from the cooling confines of winter and an open invitation to pleasant spring weather in Longmont. This month experiences the highest recorded rainfall of the year, accumulating to 1.69" (43mm) spread over an average of 15 days. Weather in May »Weather in June
June brings with it the start of the summer season and warmer temperatures in Longmont. The transition from spring to summer is marked with decreased rainfall, registering at 0.94" (24mm) distributed over 11.2 days. It's an ideal period to indulge in outdoor excursions as June boasts extended daylight hours and sunny weather, thrilling both residents and visitors. Weather in June »Weather in July
July is the zenith of the summer season in Longmont, reflecting the highest temperatures and peak solar intensity. Weather conditions, not surprisingly, indicate an increase in rainfall to 1.54" (39mm), which spans an average of 16 days. Weather in July »Weather in August
August presents another month of the summer season in Longmont with the temperature slightly decreasing compared to July, yet still maintaining a strong hold on the warmth. Rainfall slightly decreases to 0.98" (25mm) over 13.3 days, indicating a transition towards the impending autumn season. Weather in August »Weather in September
September signals the onset of the autumn season in Longmont, with temperatures diminishing distinctly from the earlier summer highs. The weather remains pleasant and rainfall levels decrease to 0.75" (19mm), falling over an average of 9.7 days. Weather in September »Weather in October
Entering October, Longmont sees the beauty of fall in all its glory. This month marks a significant decrease in temperatures, veering towards the colder side of the year. The falling leaves and shorter days hint toward the incoming winter season, with rainfall settling at 0.67" (17mm) over 5.9 days. Weather in October »Weather in November
November in Longmont witnesses the transition from autumn towards the colder winter season. The temperature falls noticeably, and snowfall returns with a total of 4.41" (112mm) scattered over 5.4 days, creating a stark contrast to the previous months. Weather in November »Weather in December
December manifests the winter season in its entire splendor in Longmont. As temperatures drop further, the city experiences an increment in snow accumulation up to 3.03" (77mm) over 6.1 days relative to its predecessor. As the year concludes, the city gleams under the holiday lights, reclining under a fresh blanket of snow. Weather in December »Updated: Feb 10, 2024
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Published by: Weather Atlas | About Us
Data Sources | Weather Forecasting & Climate
Frequently asked questions
January is the month with the least rainfall in Longmont. Rain falls for 3.5 days and accumulates 0.35" (9mm) of precipitation.
Throughout the year, there are 105.4 rainfall days, and 10.43" (265mm) of precipitation is accumulated.
Months with snowfall are January through May, October through December.
In Longmont, during the entire year, snow falls for 37.1 days and aggregates up to 26.73" (679mm) of snow.
January, February, November and December, with an average maximum UV index of 2, are months with the lowest UV index.
The most humid month is February, with an average relative humidity of 66%.
The month with the least sunshine is February, with an average of 6.8h of sunshine.
On Sunday, March 10. 2024, at 2:00 am, Daylight Saving Time starts in Longmont, 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.
May is the month with the most rainfall in Longmont. Rain falls for 15 days and accumulates 1.69" (43mm) of precipitation.
In Longmont, snow does not fall in June through September.
With an average of 15h and 0min of daylight, June has the longest days of the year.
With an average of 11.9h of sunshine, June has the most sunshine of the year.
July tends to be the warmest month, with temperatures averaging a daily high of 85.6°F (29.8°C) and a low of 59.2°F (15.1°C).
July and August, with an average maximum UV index of 6, are months with the highest UV index in Longmont.
August is the least humid month in Longmont, with an average relative humidity of 42%.
The month with the most snowfall in Longmont is November, when snow falls for 5.4 days and typically aggregates up to 4.41" (112mm) of snow.
Longmont's coldest month, December, registers temperatures that range from a high of 39°F (3.9°C) to a low of 19.9°F (-6.7°C).
December has the shortest days of the year, with an average of 9h and 24min of daylight.
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).
Average pressure
Longmont, CO
- Average pressure in January:
30.15"Hg - Average pressure in February:
30.08"Hg - Average pressure in March:
30"Hg - Average pressure in April:
29.91"Hg - Average pressure in May:
29.92"Hg - Average pressure in June:
29.91"Hg
- Average pressure in July:
29.99"Hg - Average pressure in August:
30"Hg - Average pressure in September:
30"Hg - Average pressure in October:
30.03"Hg - Average pressure in November:
30.08"Hg - Average pressure in December:
30.12"Hg
The month with the highest atmospheric pressure is January (30.15"Hg).
The months with the lowest atmospheric pressure are April and June (29.91"Hg).
Average wind speed
Longmont, CO
- Average wind speed in January:
6.2mph - Average wind speed in February:
6mph - Average wind speed in March:
6.6mph - Average wind speed in April:
6.6mph - Average wind speed in May:
5.9mph - Average wind speed in June:
6mph
- Average wind speed in July:
5.7mph - Average wind speed in August:
5.6mph - Average wind speed in September:
5.6mph - Average wind speed in October:
5.7mph - Average wind speed in November:
5.9mph - Average wind speed in December:
5.7mph
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).
Average humidity
Longmont, CO
The month with the highest relative humidity is February (66%).
The month with the lowest relative humidity is August (42%).
Average rainfall
Longmont, CO
- Average rainfall in January:
0.35" - Average rainfall in February:
0.51" - Average rainfall in March:
0.83" - Average rainfall in April:
1.14" - Average rainfall in May:
1.69" - Average rainfall in June:
0.94"
- Average rainfall in July:
1.54" - Average rainfall in August:
0.98" - Average rainfall in September:
0.75" - Average rainfall in October:
0.67" - Average rainfall in November:
0.63" - Average rainfall in December:
0.39"
The wettest month (with the highest rainfall) is May (1.69").
The driest month (with the least rainfall) is January (0.35").
Average rainfall days
Longmont, CO
- Average rainfall days in January:
3.5 days - Average rainfall days in February:
3.6 days - Average rainfall days in March:
7.7 days - Average rainfall days in April:
10.7 days - Average rainfall days in May:
15 days - Average rainfall days in June:
11.2 days
- Average rainfall days in July:
16 days - Average rainfall days in August:
13.3 days - Average rainfall days in September:
9.7 days - Average rainfall days in October:
5.9 days - Average rainfall days in November:
4.1 days - Average rainfall days in December:
4.7 days
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).
Average snowfall
Longmont, CO
The month with the highest snowfall is November (4.41").
The months with the least snowfall are June, July, August and September (0").
Average snowfall days
Longmont, CO
- Average snowfall days in January:
5.8 days - Average snowfall days in February:
7.7 days - Average snowfall days in March:
4.9 days - Average snowfall days in April:
3.3 days - Average snowfall days in May:
1.3 days - Average snowfall days in June:
0 days
- Average snowfall days in July:
0 days - Average snowfall days in August:
0 days - Average snowfall days in September:
0.1 days - Average snowfall days in October:
2.5 days - Average snowfall days in November:
5.4 days - Average snowfall days in December:
6.1 days
The month with the highest number of snowfall days is February (7.7 days).
The months with the least snowfall days are June, July and August (0 days).
Average daylight / Average sunshine
Longmont, CO
- Average daylight in January:
9h and 42min - Average daylight in February:
10h and 42min - Average daylight in March:
12h and 0min - Average daylight in April:
13h and 18min - Average daylight in May:
14h and 24min - Average daylight in June:
15h and 0min
- Average daylight in July:
14h and 42min - Average daylight in August:
13h and 42min - Average daylight in September:
12h and 24min - Average daylight in October:
11h and 6min - Average daylight in November:
10h and 0min - Average daylight in December:
9h and 24min
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:
7h and 6min - Average sunshine in February:
6h and 48min - Average sunshine in March:
9h and 0min - Average sunshine in April:
10h and 42min - Average sunshine in May:
11h and 0min - Average sunshine in June:
11h and 54min
- Average sunshine in July:
11h and 48min - Average sunshine in August:
11h and 42min - Average sunshine in September:
11h and 0min - Average sunshine in October:
7h and 24min - Average sunshine in November:
7h and 18min - Average sunshine in December:
6h and 54min
The month with the most sunshine is June (Average sunshine: 11h and 54min).
The month with the least sunshine is February (Average sunshine: 6h and 48min).
Average sunshine days
Longmont, CO
- Average sunshine days in January:
23.4 days - Average sunshine days in February:
18.7 days - Average sunshine days in March:
18.8 days - Average sunshine days in April:
15.3 days - Average sunshine days in May:
13 days - Average sunshine days in June:
15.1 days
- Average sunshine days in July:
9.3 days - Average sunshine days in August:
11.6 days - Average sunshine days in September:
16.5 days - Average sunshine days in October:
20.6 days - Average sunshine days in November:
22.4 days - Average sunshine days in December:
22.5 days
The month with the most sunshine days is January (23.4 days).
The month with the least sunshine days is July (9.3 days).
Average UV index
Longmont, CO
The months with the highest UV index are July and August (UV index 6).
The months with the lowest UV index are January, February, November and December (UV index 2).
Average cloud cover
Longmont, CO
The months with the most cloud cover are April and May (Cloud cover 26).
The months with the least cloud cover are June and September (Cloud cover 16).
Average visibility
Longmont, CO
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).
