Hail history for Slippery Rock, Pennsylvania
NOAA hail reports in and within about 5 km (3 miles) of Slippery Rock since 1987, with preliminary reports to November 3, 2026.
Readout · Slippery Rock
- Last hail
- Apr 14, 2024
- 0.75 in, penny size
- Hail days, last 5 years
- 1
- since Nov 3, 2021 · 3 reports
- Largest ever
- 1.75 in
- golf ball · Apr 14, 2024
12 reports on 10 days since 1987 · #71 of 108 Pennsylvania places
Hail map · Slippery Rock
- Under 1 in
- 1–1.75 in
- 1.75–2.5 in
- 2.5–4 in
- 4 in +
- No size
For homeowners
Roof damage after hail? Get a free inspection
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 Slippery Rock is from April 14, 2024. A local roofer can check and document it at no cost.
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What the record says about Slippery Rock
The latest hail report in and around Slippery Rock is from April 14, 2024, 0.75 in (penny size). Since November 3, 2021 there has been one hail day; the biggest stones in that time were 1.75 in on April 14, 2024.
Over the 20 years 2006–2025, Slippery Rock logged 9 reports on 7 hail days, about 0.5 reports a year. That is about the same as the median Pennsylvania town on this site (0.5 a year) and ranks #71 of 108 Pennsylvania cities and towns on this site for all-time reports. Slippery Rock accounts for 6% of the 201 reports filed in Butler County.
0% of reports with a size were 2 inches (hen egg) or larger, against 0% for the median Pennsylvania town on this site. The largest hail on record here is 1.75 in (golf ball) on April 14, 2024 near 0.52 W Slippery Rock.
Reports were up 100% in 2016–2025 (6) compared with 2006–2015 (3). The busiest year was 2024, with 3 reports on 1 day. Hail here peaks in April (33% of reports); 58% fall between April and June.
Reports a year 2006–2025 average
- Slippery Rock 0.5
- Butler County 6.7
- Median Pennsylvania town on this site 0.5
Hail days 2006–2025
- Slippery Rock 7
- Butler County 43
- Median Pennsylvania town on this site 6
Share 2 in or larger of sized reports
- Slippery Rock 0%
- Butler County 3%
- Median Pennsylvania town on this site 0%
Hail over time
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | 0 | ||||||||||||
| 2025 | 0 | ||||||||||||
| 2024 | 3 | 3 | |||||||||||
| 2023 | 0 | ||||||||||||
| 2022 | 0 | ||||||||||||
| 2021 | 1 | 1 | 2 | ||||||||||
| 2020 | 1 | 1 | |||||||||||
| 2019 | 0 | ||||||||||||
| 2018 | 0 | ||||||||||||
| 2017 | 0 |
Hail days since Nov 3, 2021
| Date | Reports | Largest | Storm page |
|---|---|---|---|
| Apr 14, 2024 | 3 | 1.75 in | — |
Largest hail on record
| Date | Size | Location | County | Time · source |
|---|---|---|---|---|
| Apr 14, 2024 | 1.75 ingolf ball | 0.52 W Slippery Rock | Butler | 17:32 local · NCEI |
| Apr 14, 2024 | 1.75 ingolf ball | 0.52 W Slippery Rock | Butler | 17:25 local · NCEI |
| Apr 9, 2001 | 1.75 ingolf ball | Slippery Rock | Butler | 14:12 local · NCEI |
| Mar 28, 2020 | 1.00 inquarter | 0.52 W Slippery Rock | Butler | 13:00 local · NCEI |
| Jul 17, 2010 | 1.00 inquarter | 0.52 W Slippery Rock | Butler | 18:40 local · NCEI |
Size of every report
- Under 1 in 5 42%
- 1–2 in 7 58%
- 2 in + 0 0%
Most recent reports
| Date | Size | Location | County | Time · source |
|---|---|---|---|---|
| Apr 14, 2024 | 0.75 inpenny | 0.52 W Slippery Rock | Butler | 18:13 local · NCEI |
| Apr 14, 2024 | 1.75 ingolf ball | 0.52 W Slippery Rock | Butler | 17:32 local · NCEI |
| Apr 14, 2024 | 1.75 ingolf ball | 0.52 W Slippery Rock | Butler | 17:25 local · NCEI |
| Aug 12, 2021 | 0.75 inpenny | 0.52 W Slippery Rock | Butler | 16:43 local · NCEI |
| Jun 14, 2021 | 0.75 inpenny | 0.52 W Slippery Rock | Butler | 13:33 local · NCEI |
| Mar 28, 2020 | 1.00 inquarter | 0.52 W Slippery Rock | Butler | 13:00 local · NCEI |
| Jul 17, 2010 | 1.00 inquarter | 0.52 W Slippery Rock | Butler | 18:40 local · NCEI |
| Jul 27, 2007 | 1.00 inquarter | Slippery Rock | Butler | 21:20 local · NCEI |
| Mar 13, 2006 | 1.00 inquarter | Slippery Rock | Butler | 15:14 local · NCEI |
| Jun 5, 2002 | 0.75 inpenny | Slippery Rock | Butler | 16:00 local · NCEI |
| Apr 9, 2001 | 1.75 ingolf ball | Slippery Rock | Butler | 14:12 local · NCEI |
| May 30, 1987 | 0.75 inpenny | — | Butler | 12:50 local · NCEI |
Hail history near Slippery Rock
- Grove City 10 km · 17
- Mercer 23 km · 18
- New Wilmington 24 km · 12
- Homeacre-Lyndora 25 km · 10
- New Castle 26 km · 42
- Butler 27 km · 16
- Harmony 30 km · 11
- Sandy Lake 31 km · 11
Questions about hail in Slippery Rock
How often does it hail in Slippery Rock, Pennsylvania?
12 hail reports have been logged in and within about 5 km (3 miles) of Slippery Rock since 1987. Over the 20 years 2006–2025 that averages 0.5 reports a year. That ranks #71 of 108 Pennsylvania places by number of reports.
When is hail season in Slippery Rock?
Most reports come in April, March, June. April alone accounts for 33% of all reports.
What is the largest hail recorded in Slippery Rock?
1.75 in (golf ball size) on April 14, 2024 near 0.52 W Slippery Rock. 0% of reports here were 2 inches or larger.
When did it last hail in Slippery Rock?
The most recent report in this data is from April 14, 2024 (0.75 in). Final NOAA data runs to July 31, 2026; preliminary NWS reports run to November 3, 2026.
How many hail storms has Slippery Rock had in the last five years?
1 separate days with hail reports since November 3, 2021, adding up to 3 reports. The most recent was April 14, 2024.
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.