May weather forecast
Longmont, CO

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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. Blossoms achieve full bloom, and migrating birds return, making it a popular choice for outdoor activities and reconnecting with nature. With longer daylight hours, Longmont highlights the vitality of the locale, embracing the dynamic environment of the spring season.

Temperature

Longmont's May weather indicates a minor ascent in high-temperatures, adjusting from a mild 57.7°F (14.3°C) in April to a comfortable 66.4°F (19.1°C). Longmont, amid May nights, sees a noteworthy disparity from daily highs with an average temperature of 42.6°F (5.9°C).

Humidity

In May, the average relative humidity in Longmont, Colorado, is 54%.

Rainfall

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

Snowfall

Months with snowfall are January through May, October through December. May is the last month it regularly snows. During 1.3 snowfall days, in May, Longmont aggregates 1.42" (36mm) of snow. Throughout the year, there are 37.1 snowfall days, and 26.73" (679mm) of snow is accumulated.

Daylight

In May, the average length of the day in Longmont is 14h and 25min.
On the first day of the month, sunrise is at 5:58 am and sunset at 7:55 pm. On the last day of May, sunrise is at 5:33 am and sunset at 8:23 pm MDT.

Sunshine

In Longmont, Colorado, the average sunshine in May is 11h.

UV index

The average daily maximum UV index in May is 5. A UV Index of 3 to 5 symbolizes a medium health hazard from unsafe exposure to UV radiation for average individuals.
Note: In May, a regular UV index of 5 translates into these guidelines:
Be cautious. Those with fair skin can be subjected to burns in fewer than 30 minutes. Midday Sun has the strongest UV rays, making it crucial to limit exposure and find shade. Combat UV radiation's detrimental effects with sun-safe clothing and UV-blocking eyewear. Mind this! Nearly twice the UV radiation from the Sun can be reflected by the snow.
Updated: Feb 10, 2024
Published by: Weather U.S. | About Us
Data Sources | Weather Forecasting & Climate

Frequently asked questions

What are the temperatures in Longmont in May?

The average high-temperature and low-temperature in Longmont, Colorado, during May are 66.4°F (19.1°C) and 42.6°F (5.9°C) respectively.

What is the average humidity in May in Longmont?

In May, the average relative humidity in Longmont, Colorado, is 54%.

What is the rainiest month in Longmont?

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

How much does it rain in Longmont in May?

In Longmont, Colorado, in May, during 15 rainfall days, 1.69" (43mm) of precipitation is typically accumulated.

What is the last month it snows in Longmont?

May is the last month it regularly snows. During 1.3 snowfall days, in May, Longmont aggregates 1.42" (36mm) of snow.

How many hours of daylight does Longmont have in May?

In May, the average day length in Longmont, Colorado, is 14h and 25min.

When is the sunrise / sunset in May in Longmont?

On the first day of May, sunrise is at 5:58 am and sunset at 7:55 pm. On the last day of the month, sunrise is at 5:33 am and sunset at 8:23 pm MDT.

How long on average sun shines in May in Longmont?

In May, the average sunshine duration in Longmont is 11h.

How high is the UV index in May in Longmont?

In May, the average daily maximum UV index in Longmont is 5. A UV Index estimate of 3 to 5 represents a moderate vulnerability from exposure to Sun's UV rays.
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 May
Longmont, CO

Average temperature in May - Longmont, CO
  • Average high temperature in May: 66.4°F

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).

  • Average low temperature in May: 42.6°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 in May
Longmont, CO

Average pressure in May - Longmont, CO
  • Average pressure in May: 29.92"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 in May
Longmont, CO

Average wind speed in May - Longmont, CO
  • Average wind speed in May: 5.9mph

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 in May
Longmont, CO

Average humidity in May - Longmont, CO
  • Average humidity in May: 54%

The month with the highest relative humidity is February (66%).
The month with the lowest relative humidity is August (42%).

Average rainfall in May
Longmont, CO

Average rainfall in May - Longmont, CO
  • Average rainfall in May: 1.69"

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 in May
Longmont, CO

Average rainfall days in May - Longmont, CO
  • Average rainfall days in May: 15 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 in May
Longmont, CO

Average snowfall in May - Longmont, CO
  • Average snowfall in May: 1.42"

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 in May
Longmont, CO

Average snowfall days in May - Longmont, CO
  • Average snowfall days in May: 1.3 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 in May /
Average sunshine in May
Longmont, CO

Average daylight in May / Average sunshine in May - Longmont, CO
  • Average daylight in May: 14h and 2min

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 May: 11h and 0min

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 in May
Longmont, CO

Average sunshine days in May - Longmont, CO
  • Average sunshine days in May: 13 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 in May
Longmont, CO

Average UV index in May - Longmont, CO
  • Average UV index in May: 5

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 in May
Longmont, CO

Average cloud cover in May - Longmont, CO
  • Average cloud cover in May: 26

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 in May
Longmont, CO

Average visibility in May - Longmont, CO
  • Average visibility in May: 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).

Longmont, Colorado, USA

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