Hail History

Hail history for Boulder, Colorado

NOAA hail reports in and within about 5 km (3 miles) of Boulder since 1962, with preliminary reports to November 3, 2026.

Readout · Boulder

Last hail
May 18, 2025
1.00 in, quarter size
Hail days, last 5 years
5
since Nov 3, 2021 · 7 reports
Largest ever
2.75 in
baseball · Jun 17, 1979

85 reports on 51 days since 1962 · #16 of 183 Colorado places

Hail map · Boulder

Boulder Gunbarrel Louisville Niwot Lafayette Erie Broomfield Longmont 10 mi
  • Under 1 in
  • 1–1.75 in
  • 1.75–2.5 in
  • 2.5–4 in
  • 4 in +
  • No size
85 most recent reports with a location; Boulder County is shaded. Open street map

For homeowners

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Hail bruises shingles and cracks seals in ways you can't see from the ground, and most insurers set a claim deadline after the storm. The latest hail report in Boulder is from May 18, 2025. A local roofer can check and document it at no cost.

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What the record says about Boulder

The latest hail report in and around Boulder is from May 18, 2025, 1.00 in (quarter size). Since November 3, 2021 there have been 5 separate hail days; the biggest stones in that time were 1.00 in on May 18, 2025.

Over the 20 years 2006–2025, Boulder logged 51 reports on 24 hail days, about 2.5 reports a year. That is 3.2 times the median Colorado town on this site (0.8 a year) and ranks #16 of 183 Colorado cities and towns on this site for all-time reports. Boulder accounts for 24% of the 357 reports filed in Boulder County.

7% of reports with a size were 2 inches (hen egg) or larger, against 8% for the median Colorado town on this site. The largest hail on record here is 2.75 in (baseball) on June 17, 1979.

Reports were up 100% in 2016–2025 (34) compared with 2006–2015 (17). The busiest year was 2018, with 13 reports on 3 days. Hail here peaks in June (38% of reports); 56% fall between April and June.

Reports a year 2006–2025 average

  • Boulder 2.5
  • Boulder County 10.4
  • Median Colorado town on this site 0.8

Hail days 2006–2025

  • Boulder 24
  • Boulder County 66
  • Median Colorado town on this site 11

Share 2 in or larger of sized reports

  • Boulder 7%
  • Boulder County 7%
  • Median Colorado town on this site 8%

Hail over time

051015 1962: 2 reports, largest 1.75 in 1967: 4 reports, largest 2.00 in 1969: 1 reports, largest 2.75 in 1970 1973: 3 reports, largest 1.00 in 1977: 1 reports, largest 1.25 in 1979: 1 reports, largest 2.75 in 1980: 1 reports, largest 1.00 in 1980 1982: 2 reports, largest 1.25 in 1983: 2 reports, largest 2.50 in 1987: 1 reports, largest 0.75 in 1989: 1 reports, largest 0.75 in 1990: 1 reports, largest 0.75 in 1990 1991: 1 reports, largest 0.75 in 1997: 6 reports, largest 1.25 in 1998: 2 reports, largest 0.75 in 2000 2001: 1 reports, largest 0.75 in 2003: 2 reports, largest 0.88 in 2004: 2 reports, largest 0.75 in 2006: 6 reports, largest 2.50 in 2007: 5 reports, largest 1.00 in 2009: 1 reports, largest 0.88 in 2010: 1 reports, largest 0.88 in 2010 2013: 3 reports, largest 1.50 in 2014: 1 reports, largest 1.50 in 2016: 1 reports, largest 1.00 in 2017: 2 reports, largest 0.88 in 2018: 13 reports, largest 2.00 in 2019: 11 reports, largest 1.75 in 2020 2022: 1 reports, largest 0.75 in 2023: 3 reports, largest 1.00 in 2024: 1 reports, largest 0.75 in 2025: 2 reports, largest 1.00 in
Reports per year, 1962–2026. Bar colour shows the largest hail that year. Reporting grew sharply after the mid-1990s, so early decades undercount.
010203040 Jan Feb March: 1 reports (1%) Mar April: 3 reports (4%) Apr May: 13 reports (15%) May June: 32 reports (38%) Jun July: 23 reports (27%) Jul August: 8 reports (9%) Aug September: 2 reports (2%) Sep October: 3 reports (4%) Oct Nov Dec
All 85 reports by calendar month.
Reports per month, 2017–2026. Darker cells had more reports.
YearJanFebMarAprMayJunJulAugSepOctNovDecTotal
2026 0
2025 2 2
2024 1 1
2023 3 3
2022 1 1
2021 0
2020 0
2019 110 11
2018 310 13
2017 2 2

Hail days since Nov 3, 2021

DateReportsLargestStorm page
May 18, 2025 2 1.00 in —
May 30, 2024 1 0.75 in —
Jun 21, 2023 1 1.00 in —
Jun 12, 2023 2 1.00 in —
Oct 1, 2022 1 0.75 in —

Largest hail on record

Largest hail reports in Boulder
Date Size Location County Time · source
Jun 17, 1979 2.75 inbaseball — Boulder 17:05 local · NCEI
Jun 10, 1969 2.75 inbaseball — Boulder 15:22 local · NCEI
Jun 24, 2006 2.50 intennis ball 2 SW Boulder Boulder 16:50 local · NCEI
Jul 7, 1983 2.50 intennis ball — Boulder 20:00 local · NCEI
Jun 18, 2018 2.00 inhen egg 2.96 SE Boulder Arpt Boulder 18:45 local · NCEI

Sizes filed before 1996 are often rough estimates (round numbers like 7.00 or 8.00 in) without an exact spot; they are shown as NOAA filed them.

Size of every report

Most recent reports

Most recent hail reports in Boulder
Date Size Location County Time · source
May 18, 2025 1.00 inquarter 2.61 NW Marshall Boulder 14:16 local · NCEI
May 18, 2025 0.75 inpenny 2.11 NW Marshall Boulder 14:15 local · NCEI
May 30, 2024 0.75 inpenny 2.14 NNE Boulder Arpt Boulder 19:55 local · NCEI
Jun 21, 2023 1.00 inquarter 2.61 SE Boulder Boulder 17:11 local · NCEI
Jun 12, 2023 1.00 inquarter 0.53 W Boulder Boulder 11:53 local · NCEI
Jun 12, 2023 1.00 inquarter 0.69 S Boulder Boulder 11:44 local · NCEI
Oct 1, 2022 0.75 inpenny 1.06 W Boulder Arpt Boulder 14:26 local · NCEI
Jul 5, 2019 1.00 inquarter 2.07 S Boulder Arpt Boulder 18:55 local · NCEI
Jul 5, 2019 1.75 ingolf ball 3.19 NNW Louisville Boulder 18:40 local · NCEI
Jul 5, 2019 1.00 inquarter 1.26 ENE Boulder Boulder 18:39 local · NCEI
Jul 5, 2019 1.25 inhalf dollar 2.14 SSE Boulder Boulder 18:35 local · NCEI
Jul 5, 2019 1.25 inhalf dollar 1.26 ENE Boulder Boulder 18:34 local · NCEI

Hail history near Boulder

Questions about hail in Boulder

How often does it hail in Boulder, Colorado?

85 hail reports have been logged in and within about 5 km (3 miles) of Boulder since 1962. Over the 20 years 2006–2025 that averages 2.5 reports a year. That ranks #16 of 183 Colorado places by number of reports.

When is hail season in Boulder?

Most reports come in June, July, May. June alone accounts for 38% of all reports.

What is the largest hail recorded in Boulder?

2.75 in (baseball size) on June 17, 1979. 7% of reports here were 2 inches or larger.

When did it last hail in Boulder?

The most recent report in this data is from May 18, 2025 (1.00 in). Final NOAA data runs to July 31, 2026; preliminary NWS reports run to November 3, 2026.

How many hail storms has Boulder had in the last five years?

5 separate days with hail reports since November 3, 2021, adding up to 7 reports. The most recent was May 18, 2025.

Where does this hail data come from?

Hail reports come from the NOAA NCEI Storm Events Database, which the National Weather Service compiles from spotter, public, law enforcement and media reports. Recent days use preliminary NWS Local Storm Reports via the Iowa Environmental Mesonet until NOAA publishes final data. Only reported hail is counted, so areas with fewer people tend to have fewer reports.