Musselshell County was hit as recently as 2026-07-16, 15 days ago. Musselshell County is hit in most years. The largest stone on record here is 4.25 inches and 4.2 times the National Weather Service's 1 inch severe criterion, reported on 2018-05-31 near Roundup.
Colored swath = NOAA MRMS radar-estimated hail size; dots = NOAA SPC reports in Montana. Radar-indicated, not a guarantee of damage.
The last hail here fell on 2026-07-16, around Lavina. A free SwathIQ account -- hand-reviewed, invite within 24-48h -- pulls Musselshell County addresses inside a hail swath above your size threshold into a door-knock list you can export, scoped to your approved markets.
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See call-center options ->NOAA's Storm Prediction Center has logged 30 separate hail days here since 2010 -- 1.8 a year over 17 years of record. Those days carry 89 separate reports between them, two or three on a typical one. 3 of those 17 years produced none at all. The busiest single year was 2018, with 4 hail days. The last five years track the long-run rate, with 7 days since 2022.
7 of the 30 days reached 2 inches or more -- 23%, or about one hail day in 4, the last on 2022-07-09. They land in the same month as everything else, July. More than half of every hail day on record here -- 15 of 30 -- reached golf-ball size, 1.75 inches or bigger.
Across the whole of Montana, see the Montana hail map and history.
Reports cluster nearest Roundup -- 23 of the county's 30 hail days -- then Delphia (6), Melstone (6), Lavina (5) and Musselshell (3). That one town is named on 77% of them. Beyond those, NOAA names Klein and Nnw Roundup on more than one hail day apiece.
| Place | Hail days since 2010 | Largest stone |
|---|---|---|
| Roundup | 4 | 4.25″ |
| 11 Nne Roundup | 4 | 2.75″ |
| 1 NNW Roundup | 4 | 1.75″ |
| Melstone | 4 | 1.75″ |
| 3 W Delphia | 3 | 2.75″ |
The season runs June through July: 24 of the 30 hail days on record fall in those 2 months (80%). July is the single busiest month, with 13 of them (43%). Hail has also been reported in May and August, outside that window. Reports span 4 of the 12 calendar months; the other 8 have never produced one.
| Month | Hail days |
|---|---|
| May | 5 |
| June | 11 |
| July | 13 |
| August | 1 |
That day put 1 report on the map, the biggest 1.75 inches near Lavina. 2 hail days have already been reported this year.
| Date | Max hail | Reports |
|---|---|---|
| 2026-07-16 | 1.75″ | 1 |
| 2026-07-07 | 1.50″ | 2 |
| 2025-07-28 | 1.75″ | 3 |
| 2025-06-15 | 1.00″ | 1 |
| 2024-06-27 | 1.00″ | 1 |
| 2022-07-09 | 2.00″ | 8 |
| 2022-07-06 | 1.00″ | 1 |
| 2021-06-10 | 1.75″ | 2 |
The colored swath is NOAA's MRMS radar estimate of the largest hail per ~1 km cell; the dots are SPC ground reports. Yellow is about an inch, red 1.5 to 2″, purple 2″ and up (hail size vs roof damage). On this county's worst day the reports reached 4.25 inches, which is the purple band. Look up a street address with the hail history by address tool.
The nearest counties with a page of their own: Golden Valley County (21 hail days), Petroleum County (30) and Yellowstone County (53). Musselshell County sits in between.
Golden Valley County · Petroleum County · Yellowstone County
Back to the Montana hail map or the U.S. hail map.
Data & method: NOAA/NWS Storm Prediction Center reports + NOAA MRMS MESH radar, Musselshell County, Montana only. Radar-indicated and observation-based -- informational only, not a guarantee of damage or a valid claim.