Hail size chart
Short answer
A hail size chart turns the object a spotter compares hail to into a diameter in inches: pea 0.25, penny 0.75, quarter 1.00, golf ball 1.75, baseball 2.75 and grapefruit 4.50.1,2,3 Hail 1 inch (quarter size) or larger is severe, and larger sizes bring more serious warnings and more roof damage.4
Cloudbreak team · Updated October 26, 2026 · 4 min read · 14 sources
Hail size chart
The Storm Prediction Center (SPC) uses these sizes to turn hail reports into diameters. Its table starts at marble (0.50 inch); the NWS glossary adds pea (0.25 inch).1,5
| Object | Diameter (inches) | Diameter (mm) |
|---|---|---|
| Pea | 0.25 | 6 |
| Marble or mothball | 0.50 | 13 |
| Penny | 0.75 | 19 |
| Nickel | 0.88 | 22 |
| Quarter | 1.00 | 25 |
| Half dollar | 1.25 | 32 |
| Walnut or ping pong ball | 1.50 | 38 |
| Golf ball | 1.75 | 44 |
| Hen egg | 2.00 | 51 |
| Tennis ball | 2.50 | 64 |
| Baseball | 2.75 | 70 |
| Tea cup | 3.00 | 76 |
| Softball | 4.00 | 102 |
| Grapefruit | 4.50 | 114 |
NWS Storm Data instructions list the same sizes, but give pea as 0.25 to 0.375 inch and use lime for 2.00 inches and large apple for 3.00.2
Objects are rough guides: softballs range from 3.50 to 5.09 inches.2
Severe hail starts at 1 inch
The NWS issues a Severe Thunderstorm Warning for hail 1 inch (quarter size) in diameter or larger, or wind gusts of 58 mph or more.4
The SPC counts a thunderstorm with hail 2 inches or larger as "significant severe."6
Storm Data records all hail 0.75 inch or larger, but sizes under 1 inch are not used to verify warnings.2
Hail size in NWS warnings
Warnings end with coded tags such as "HAIL THREAT...RADAR INDICATED" and "MAX HAIL SIZE...1.00 IN," and the warning text names sizes by object, as in "tennis ball size hail was reported."4
Since August 2, 2021, warnings also carry a damage threat category set by hail size or wind speed: base, considerable or destructive.7
| Hail size | Damage threat tag | Default property impact statement |
|---|---|---|
| 1.00 to 1.50 inches (quarter to ping pong ball) | Base (no tag shown) | Damage to vehicles is expected. |
| 1.75 to 2.50 inches (golf ball to tennis ball) | Considerable | Expect damage to roofs, siding, windows, and vehicles. |
| 2.75 inches or larger (baseball and up) | Destructive | Expect shattered windows, extensive damage to roofs, siding, and vehicles. |
Local offices may adjust the default statements for local conditions. A Destructive tag also sends a Wireless Emergency Alert to phones in the warned area.
Hail size and roof damage
The hail size that starts to damage a roof depends on the covering, according to impact tests and field surveys presented at a 2002 American Meteorological Society conference.8
| Roof covering | Hail diameter (inches) |
|---|---|
| 3-tab asphalt shingles | 1.00 |
| 30-year laminated shingles | 1.25 |
| Cedar shingles | 1.25 |
| Medium cedar shakes | 1.50 |
| Fiber-cement tiles | 1.50 |
| Concrete tiles | 1.75 |
| Built-up roofing with gravel | 2.50 |
Lighter, thinner and older products have the lowest thresholds, and wind-driven hail can also tear siding and break windows.
How hail size is measured and reported
Hail size means diameter, measured across the widest part of the stone. Spotters are asked to report the largest stone and any damage, and a ruler is better than comparing hail to an object.
Local NWS offices send reports out as Local Storm Reports, which feed the SPC's daily Storm Reports page. The public can also report hail size through mPING, a free NOAA app; reports are anonymous and placed in time and space by GPS.9
Reports are more numerous in and around population centers and road networks, so raw report maps can overstate hail where more people live and miss it where few do.
Storm Data sizes also cluster at common reference objects such as 1, 1.75 and 2.75 inches, because reports are entered as the nearest reference object.10
Finding past hail reports for a location
The SPC Storm Reports page lists preliminary reports for any date back to June 1, 1999, entered as YYMMDD.11,12
Each page covers 1200 UTC to 1159 UTC the next day (7 a.m. to 7 a.m. CDT), so an overnight storm can appear under the previous date.6,11
Times are in UTC, hail sizes are in hundredths of an inch (75 means 0.75 inch), and each report gives latitude and longitude to two decimals.6,12
The list misses events with no Local Storm Report or with one sent more than 10 days late.6
The NCEI Storm Events Database holds the official, final NWS Storm Data, with hail records from 1955.6,13
Hail is recorded by county, and counties can be chosen on a map or from drop-down lists.
Events take 3 months to appear in the database.14
How Cloudbreak helps
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Sources
Written by the Cloudbreak team. Numbers, dates and rules cite the published sources below.
- 1. NOAA Storm Prediction Center: Hail Size as Related to Objects
- 2. NOAA National Weather Service: NWS Instruction 10-1605: Storm Data Preparation (July 26, 2021)
- 3. NOAA National Severe Storms Laboratory: Severe Weather 101: Hail Basics
- 4. NOAA National Weather Service: NWS Instruction 10-511: WFO Severe Weather Products Specification (January 26, 2023)
- 5. NOAA National Weather Service: Glossary: Hail Size
- 6. NOAA Storm Prediction Center: SPC Frequently Asked Questions
- 7. NOAA National Weather Service: New "Destructive" Severe Thunderstorm Warning Category to Trigger Wireless Emergency Alerts on Mobile Phones
- 8. American Meteorological Society, 21st Conference on Severe Local Storms: Hail Damage Threshold Sizes for Common Roofing Materials (Marshall, Herzog, Morrison and Smith, 2002)
- 9. NOAA National Severe Storms Laboratory: NSSL Projects: mPING
- 10. American Meteorological Society, via NOAA Central Library: Sub-Severe and Severe Hail (Elmore, Allen and Gerard, Weather and Forecasting, 2022)
- 11. NOAA Storm Prediction Center: Storm Prediction Center Severe Weather Summaries
- 12. NOAA Storm Prediction Center: Storm Prediction Center Today's Storm Reports
- 13. NOAA National Centers for Environmental Information: Storm Events Database: Event Types Available
- 14. NOAA National Centers for Environmental Information: Storm Events Database: Search