nomadseason

April Weather in Longmont, United States

Last updated: June 24, 2025

In Longmont, United States, the average temperature in April hovers around 9°C (48°F). Expect a wide temperature range, with a chilling minimum of -12°C (11°F) and a warm maximum reaching 29°C (85°F). Throughout the month, you can anticipate 55 mm (2.2 in) of precipitation spread over about 10 days, complemented by an average humidity of 67%.

April Temperature in Longmont

In April in Longmont, the average temperature is 9°C (48°F), with maximums reaching 29°C (85°F) and minimums plummeting as low as -12°C (11°F). This weather variation suggests travelers should be prepared for both warm days and chilly nights.

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

The chart illustrates April 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, April typically has an average temperature of 9°C (48°F), with highs reaching up to 29°C (85°F) and lows dropping to around -12°C (11°F).
JanFebMarAprMayJunJulAugSepOctNovDec303040485668747266494033
Data source: Temperature data for Longmont generated using information from the Copernicus Climate Change Service.
Choose your preferred temperature unit
The average of daily temperatures (24 hours) calculated across all days in the month.

April Precipitation in Longmont

In Longmont in April, the precipitation amount is 55 mm (2.2 in) spread over a duration of 10 days.

April Precipitation Trends in Longmont

The chart displays monthly precipitation patterns in Longmont, with values for each month alongside April’s data, which is highlighted for easy comparison. It shows the amount of precipitation, providing insights into how April’s conditions compare to those of other months. In Longmont, April typically receives around 55 mm (2.2 inches) of precipitation spread over approximately 10 days.
JanFebMarAprMayJunJulAugSepOctNovDec1926565511942314327382315
Data source: Precipitation data for April generated using information from the Copernicus Climate Change Service.
Choose your preferred precipitation unit

April Humidity in Longmont

In Longmont in April, humidity is 67%. With an average temperature of 9°C (48°F), this humidity feels like a cool blanket wrapping around you, making outdoor activities brisk and invigorating, yet requiring a light jacket to stay comfortable while exploring.

April Average Humidity in Longmont

This chart illustrates the average monthly humidity levels in Longmont, with April’s data highlighted for easy comparison. It shows the fluctuation in humidity throughout the year, helping you understand how conditions vary by season. In April, 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 April generated using information from the Copernicus Climate Change Service.

April UV Index in Longmont

In Longmont in April, 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 April

The chart shows the monthly maximum UV Index (UVI) for Longmont in April, 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 April, the maximum UV index in Longmont typically reaches 11, which falls under the extreme exposure category.
JanFebMarAprMayJunJulAugSepOctNovDec46811111212119643
Data source: Longmont April 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 April 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 April’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 April’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

Compare Longmont's Climate with Cities Worldwide