Longmont hail storm history
Boulder County·NOAA NCEI Storm Events Database·~75-day publication lag
Longmont, located in Boulder County, has experienced 7 documented hail events of 1 inch or larger over the past 10 years, with an average of 0.7 events annually. The city's position on the Colorado Front Range makes it vulnerable to afternoon convective storms that track northeast from the Rocky Mountains. The largest recorded hailstone in Longmont measured 1.25 inches in diameter.
Hail risk in Longmont peaks between May and July, with secondary activity occurring in April and August. Most significant hail events occur in the afternoon between 2 p.m. and 7 p.m. Mountain Time, when atmospheric conditions are most favorable for storm development along the Front Range.
Annual frequency — last 10 years
When hail hits — monthly pattern
Avg events per month · all years · NOAA data
All recorded hail events
Of 102 recorded events, 20 (20%) reached 1.5" or larger — the threshold for likely functional damage on standard asphalt shingles.
Report from mping.
Report from Mping.
Hail up to the size of a half dollar fell for a duration of 6 minutes.
Size was estimated.
Longmont's hail event count reflects NOAA reporting density for Boulder County, where 11 documented hail events have been recorded in official records. Smaller hailstones below 1 inch in diameter are not included in this historical analysis, so actual storm frequency may be higher than reported figures.
NOAA Storm Events Database source