Hail history for Groton, South Dakota
NOAA hail reports in and within about 5 km (3 miles) of Groton since 1963, with preliminary reports to November 3, 2026.
Readout · Groton
- Last hail
- Jun 29, 2026
- 1.00 in, quarter size
- Hail days, last 5 years
- 4
- since Nov 3, 2021 · 4 reports
- Largest ever
- 2.50 in
- tennis ball · Jun 24, 2009
24 reports on 18 days since 1963 · #82 of 305 South Dakota places
Hail map · Groton
- Under 1 in
- 1–1.75 in
- 1.75–2.5 in
- 2.5–4 in
- 4 in +
- No size
For homeowners
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What the record says about Groton
The latest hail report in and around Groton is from June 29, 2026, 1.00 in (quarter size). Since November 3, 2021 there have been 4 separate hail days; the biggest stones in that time were 1.50 in on September 29, 2023.
Over the 20 years 2006–2025, Groton logged 14 reports on 8 hail days, about 0.7 reports a year. That is 56% more than the median South Dakota town on this site (0.5 a year) and ranks #82 of 305 South Dakota cities and towns on this site for all-time reports. Groton accounts for 5% of the 445 reports filed in Brown County.
8% of reports with a size were 2 inches (hen egg) or larger, against 7% for the median South Dakota town on this site. The largest hail on record here is 2.50 in (tennis ball) on June 24, 2009 near 3.59 SSE Groton.
Reports were down 73% in 2016–2025 (3) compared with 2006–2015 (11). The busiest year was 2009, with 5 reports on 2 days. Hail here peaks in July (38% of reports); 46% fall between April and June.
Reports a year 2006–2025 average
- Groton 0.7
- Brown County 11.4
- Median South Dakota town on this site 0.5
Hail days 2006–2025
- Groton 8
- Brown County 84
- Median South Dakota town on this site 7
Share 2 in or larger of sized reports
- Groton 8%
- Brown County 7%
- Median South Dakota town on this site 7%
Hail over time
| Year | Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | Total |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2026 | 1 | 1 | |||||||||||
| 2025 | 0 | ||||||||||||
| 2024 | 1 | 1 | |||||||||||
| 2023 | 1 | 1 | |||||||||||
| 2022 | 1 | 1 | |||||||||||
| 2021 | 0 | ||||||||||||
| 2020 | 0 | ||||||||||||
| 2019 | 0 | ||||||||||||
| 2018 | 0 | ||||||||||||
| 2017 | 0 |
Hail days since Nov 3, 2021
| Date | Reports | Largest | Storm page |
|---|---|---|---|
| Jun 29, 2026 | 1 | 1.00 in | — |
| Jul 6, 2024 | 1 | 1.00 in | — |
| Sep 29, 2023 | 1 | 1.50 in | — |
| Aug 5, 2022 | 1 | 1.25 in | — |
Largest hail on record
| Date | Size | Location | County | Time · source |
|---|---|---|---|---|
| Jun 24, 2009 | 2.50 intennis ball | 3.59 SSE Groton | Brown | 19:45 local · NCEI |
| Jul 9, 2013 | 2.00 inhen egg | 2.93 SSE Groton Muni Arpt | Brown | 18:30 local · NCEI |
| Jul 9, 2013 | 1.75 ingolf ball | Groton | Brown | 18:35 local · NCEI |
| Jul 9, 2013 | 1.75 ingolf ball | Groton | Brown | 18:32 local · NCEI |
| Jul 17, 2010 | 1.75 ingolf ball | 2.76 S Groton | Brown | 15:34 local · NCEI |
Size of every report
- Under 1 in 4 17%
- 1–2 in 18 75%
- 2 in + 2 8%
Most recent reports
| Date | Size | Location | County | Time · source |
|---|---|---|---|---|
| Jun 29, 2026 | 1.00 inquarter | Groton | Brown | 07:04 local · NCEI |
| Jul 6, 2024 | 1.00 inquarter | Groton | Brown | 15:15 local · NCEI |
| Sep 29, 2023 | 1.50 inping pong ball | 1.19 NW Groton | Brown | 05:56 local · NCEI |
| Aug 5, 2022 | 1.25 inhalf dollar | Groton | Brown | 18:33 local · NCEI |
| Jul 9, 2013 | 1.75 ingolf ball | Groton | Brown | 18:35 local · NCEI |
| Jul 9, 2013 | 1.50 inping pong ball | 1.38 N Groton | Brown | 18:34 local · NCEI |
| Jul 9, 2013 | 1.75 ingolf ball | Groton | Brown | 18:32 local · NCEI |
| Jul 9, 2013 | 2.00 inhen egg | 2.93 SSE Groton Muni Arpt | Brown | 18:30 local · NCEI |
| Jul 17, 2010 | 1.75 ingolf ball | 2.76 S Groton | Brown | 15:34 local · NCEI |
| May 24, 2010 | 1.00 inquarter | Groton | Brown | 00:47 local · NCEI |
| Jun 24, 2009 | 2.50 intennis ball | 3.59 SSE Groton | Brown | 19:45 local · NCEI |
| Jun 24, 2009 | 1.00 inquarter | Groton | Brown | 19:40 local · NCEI |
Hail history near Groton
Questions about hail in Groton
How often does it hail in Groton, South Dakota?
24 hail reports have been logged in and within about 5 km (3 miles) of Groton since 1963. Over the 20 years 2006–2025 that averages 0.7 reports a year. That ranks #82 of 305 South Dakota places by number of reports.
When is hail season in Groton?
Most reports come in July, June, August. July alone accounts for 38% of all reports.
What is the largest hail recorded in Groton?
2.50 in (tennis ball size) on June 24, 2009 near 3.59 SSE Groton. 8% of reports here were 2 inches or larger.
When did it last hail in Groton?
The most recent report in this data is from June 29, 2026 (1.00 in). Final NOAA data runs to July 31, 2026; preliminary NWS reports run to November 3, 2026.
How many hail storms has Groton had in the last five years?
4 separate days with hail reports since November 3, 2021, adding up to 4 reports. The most recent was June 29, 2026.
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.