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HailIndex

Boulder hail storm history

Boulder County·NOAA NCEI Storm Events Database·~75-day publication lag

Boulder, located in Boulder County on Colorado's Front Range, has experienced 1 documented hail event of 1 inch or larger over the past 10 years. The city's elevation and geography make it vulnerable to afternoon convective storms that track northeast from the Rocky Mountains, though large hail events remain infrequent compared to other Colorado regions.

Events ≥1" (10yr)
28
Significant ≥1.5"
5
Avg per year
2.8
Largest recorded
1.75"
Most recent
Aug 23, 2025
Total records
40
NOAA storm history
events (10 yr)27
≥1.5" significant5
peak year (12)2018

Hail risk in Boulder peaks from May through July, with secondary activity in April and August. Most significant hail events occur between 2 p.m. and 7 p.m. Mountain Time, when afternoon convective storms develop and move across the Front Range toward Boulder County.

Annual frequency — last 10 years

2025
4
2024
1
2023
4
2022
2
2021
2
2020
no events
2019
9
2018
15
2017
2
≥2.0" severe≥1.5" significant≥1.0" marginal

When hail hits — monthly pattern

Avg events per month · all years · NOAA data

Jan0
Feb0
Mar0
Apr0
May11
Jun17
Jul10
Aug1
Sep0
Oct1
Nov0
Dec0

All recorded hail events

Of 40 recorded events, 5 (13%) reached 1.5" or larger — the threshold for likely functional damage on standard asphalt shingles.

Aug 23, 20250.75"penny
Jun 17, 20250.75"penny

Report from mping.

Picture of 1 inch hail on Twitter.

May 31, 20240.75"penny

The report was from mping.

Oct 1, 20220.75"penny
Jul 28, 20221"quarter
Jun 25, 20211"quarter
May 2, 20210.75"penny
Jul 15, 20190.75"penny
May 30, 20181"quarter
May 18, 20170.75"penny
May 16, 20170.88"penny
Jun 6, 20161"quarter
About this data

Boulder's hail event count is based on NOAA Storm Data records, which rely on trained spotters and reported damage. The city's low 10-year event frequency (0.1 events per year) reflects both genuine rarity and potential underreporting of smaller hail events that do not trigger formal damage assessments.

NOAA Storm Events Database source