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May Weather in Longmont, United States

Last updated: June 24, 2025

In May, the average temperature in Longmont, United States hovers around 13°C (56°F), with a minimum dipping to -4°C (25°F) and a maximum soaring to 31°C (88°F). Expect about 119 mm (4.7 in) of precipitation over 14 days, contributing to an average humidity level of 67%. Stay prepared for a spectrum of weather conditions!

May Temperature in Longmont

In May in Longmont, the average temperature is 13°C (56°F). The maximum can reach 31°C (88°F), and the minimum can be as low as -4°C (25°F). This diverse temperature range makes Longmont an exciting destination for travelers seeking both warm and cool experiences.

May Weather in Longmont: Daily Temperature Highs, Lows, and Averages

The chart illustrates May temperature patterns in Longmont, showcasing daily minimum, maximum, and average temperatures. It highlights the typical range of temperatures throughout the month, providing insights into weather trends. In Longmont, May typically has an average temperature of 13°C (56°F), with highs reaching up to 31°C (88°F) and lows dropping to around -4°C (25°F).
JanFebMarAprMayJunJulAugSepOctNovDec303040485668747266494033
Data source: Temperature data for Longmont generated using information from the Copernicus Climate Change Service.
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The average of daily temperatures (24 hours) calculated across all days in the month.

May Precipitation in Longmont

In Longmont in May, the precipitation amount is 119 mm (4.7 in) over the course of 14 days.

May Precipitation Trends in Longmont

The chart displays monthly precipitation patterns in Longmont, with values for each month alongside May’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how May’s conditions compare to those of other months. In Longmont, May typically receives around 119 mm (4.7 inches) of precipitation spread over approximately 14 days.
JanFebMarAprMayJunJulAugSepOctNovDec1926565511942314327382315
Data source: Precipitation data for May generated using information from the Copernicus Climate Change Service.
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May Humidity in Longmont

In Longmont in May humidity is 67%. With an average temperature of 13°C (56°F), this humidity feels like a damp chill that seeps into your bones, making outdoor activities a bit uncomfortable, but still manageable for travelers who embrace the cool, crisp air.

May Average Humidity in Longmont

This chart illustrates the average monthly humidity levels in Longmont, with May’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In May, average humidity in Longmont is approximately 67%, offering insight into how humid the weather typically is during this month.
JanFebMarAprMayJunJulAugSepOctNovDec84%86%75%67%67%68%62%63%63%72%80%85%
Data source: Humidity data for May generated using information from the Copernicus Climate Change Service.

May UV Index in Longmont

In Longmont in May, the maximum UV index reaches 11, which corresponds to an extreme Exposure Category. With a time to burn of just 10 minutes, it's essential to take precautions. For more details, you can check the Hourly UV Index in Longmont.

Maximum UV Index Levels in Longmont for May

The chart shows the monthly maximum UV Index (UVI) for Longmont in May, representing the highest UV radiation level. The UVI measures the intensity of ultraviolet radiation from the sun, indicating the potential risk of sunburn and UV-related health issues. In May, the maximum UV index in Longmont typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46811111212119643
Data source: Longmont May UVI data generated using information from the Copernicus Climate Change Service.

UV Risk Categories

  •  Extreme (11+): Avoid the sun, stay in shade.
  •  Very High (8-10): Limit sun exposure.
  •  High (6-7): Use SPF 30+ and protective clothing.
  •  Moderate (3-5): Midday shade recommended.
  •  Low (0-2): No protection needed.

How May Weather in Longmont Compares to Other Months

Weather in Longmont varies notably across the year, with each month offering distinct climate conditions. This page compares May’s weather to other months in Longmont, focusing on differences in temperature, rainfall, humidity, and UV levels.

This table compares monthly weather conditions in Longmont, showing how May’s temperature, precipitation, humidity, and UV index levels differ from those of other months.
 TemperaturePrecipitationHumidityUV
January Weather-1°C (30°F)19 mm (0.8 inches)84%moderate
February Weather-1°C (30°F)26 mm (1.0 inches)85%high
March Weather5°C (40°F)56 mm (2.2 inches)75%very high
April Weather9°C (48°F)55 mm (2.2 inches)67%extreme
May Weather13°C (56°F)119 mm (4.7 inches)67%extreme
June Weather20°C (69°F)42 mm (1.6 inches)68%extreme
July Weather23°C (75°F)31 mm (1.2 inches)62%extreme
August Weather22°C (73°F)43 mm (1.7 inches)63%extreme
September Weather19°C (66°F)27 mm (1.1 inches)63%very high
October Weather9°C (49°F)38 mm (1.5 inches)72%high
November Weather4°C (40°F)23 mm (0.9 inches)79%moderate
December Weather0°C (33°F)15 mm (0.6 inches)85%moderate

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