Hail history for Petroleum County, MT

Petroleum County has 115 recorded hail events in the NOAA Storm Events Database — 76 of them 1″ or larger and 11 at 2″ or larger. The largest on record: 3.5″ (softball) on June 15, 2025.

Records 1950–present Data through April 2026 Peak month July

Core sample · every recorded event, 1955–2026

Mark size = measured hail diameter; slivers are events with no recorded size. Amber ≥2″, red ≥2.75″ (baseball class). Denser recent decades partly reflect better reporting, not only more storms.

Recorded events 115 since 1963

1″ or larger 76 NWS severe threshold

2″ or larger 11 hen egg class and up

Largest recorded 3.5″ softball · June 15, 2025

Read the record honestly: Storm Events contains what was reported to the National Weather Service. Sparse or rural counties under-report, and coverage improved sharply after the mid-1990s — a quiet-looking stretch is not proof nothing fell.

When it hails in Petroleum County

Recorded events by month, 1950–present. The amber bar marks Petroleum County's peak: July.

Most recent recorded events

Latest 8 of 115 recorded events · data through April 2026
Date	Size	Comparable to
July 17, 2025	1.75″	Golf ball
July 17, 2025	2.0″	Hen egg
June 15, 2025	2.5″	Tennis ball
June 15, 2025	1.5″	Ping-pong ball
June 15, 2025	3.5″	Softball
June 15, 2025	1.75″	Golf ball
June 15, 2025	1.75″	Golf ball
June 13, 2025	1.0″	Quarter

Looking for a specific storm? Use the did-it-hail date lookup for Petroleum County.

From the storm reports

Narratives as filed with the NOAA Storm Events Database (public records; lightly trimmed for length).

July 17, 2025 · 2.0″ (hen egg)

Public reported hen egg size hail.

June 15, 2025 · 3.5″ (softball)

Large hail about 3.5 inches in diameter, lasted for about 15 mins.

August 11, 2019 · 3.0″ (tea cup)

Trained spotter reported, via social media, tea cup size hail stones (3 inches in diameter).

Events by decade

1950s	1960s	1970s	1980s	1990s	2000s	2010s	2020s
0	1	1	0	16	47	33	17

The climb across decades is largely a reporting story: spotter networks, radar, and digital filing pulled far more storms into the record after the 1990s.

Questions about hail in Petroleum County

Has it ever hailed in Petroleum County?

Yes — 115 hail events have been recorded for Petroleum County, MT in the NOAA Storm Events Database since 1963, including 76 of 1″ (quarter size) or larger.

When did it last hail in Petroleum County?

The most recent recorded hail event for Petroleum County, MT is July 17, 2025, with 1.75″ (golf ball) hail. The database is currently updated through April 2026, so a storm from the last few weeks may not appear yet. To check a specific day, use the did-it-hail date lookup.

What is the largest hail ever recorded in Petroleum County?

3.5″ (softball), recorded on June 15, 2025. Hail that size is destructive-class and typically damages roofs, vehicles, and siding. See how big that really is on the actual-size hail chart.

Does a recorded hail event mean my roof was damaged?

No. This page reports storm records, not damage. Hail size and damage vary block by block within a county, and only an inspection can establish what happened to a specific roof. If you suspect damage, talk to your insurer or a licensed roofer — they can pull the same NOAA records for your claim.

More Montana hail history

All 56 Montana counties, ranked by recorded hail →

Source: NOAA/NCEI Storm Events Database, public domain, updated monthly by NCEI — this site's copy runs through April 2026. HailHistory reports records; it does not give insurance advice or assess damage.