Reference
Hail size and damage chart
Everyday comparisons for each stone size, what it usually damages, and the two thresholds that matter.
Sizes drawn to relative scale. Everyday comparisons are approximate; hailstones are rarely perfect spheres.
Sizes and typical damage
| Diameter | Everyday comparison | Typical damage |
|---|---|---|
| Under 1 in | pea to marble | Little or no damage; nuisance for vehicles left outside. |
| 1 to 1½ in | quarter to ping-pong ball | Dents and chipped paint on vehicles; damage to tender plants. |
| 1½ to 2 in | golf ball | Vehicle dents and cracked windshields; shingle and gutter damage begins. |
| 2 to 2¾ in | hen egg to tennis ball | Widespread shingle damage, siding fractures, soft-metal dents. |
| 2¾ to 4 in | baseball to grapefruit | Severe roof and siding damage; broken windows; vehicle glass failure. |
| 4 in and larger | softball and larger | Structural damage, destroyed roofing, injury risk to people and animals outdoors. |
The two thresholds that matter
1 inch is the National Weather Service threshold for a severe thunderstorm. Below it, hail is a nuisance; at or above it, the storm is classified severe and warnings are issued. The tables on this site count reports at 2 inches and at 4 inches, so a 1-inch report is in the totals but in neither of those columns.
2 inches is where damage becomes likely rather than possible. Asphalt shingles begin to lose granules and crack, gutters and downspouts dent, and vehicle body panels and windshields take damage. Most insurance claims that follow a hailstorm involve stones in the 1.5 to 2.5 inch range, not the record-breakers.
4 inches and above is genuinely dangerous. Stones that size fall fast enough to break windows, penetrate roofing decking, and injure anyone caught outdoors. They are rare: about 0.4% of the reported events in this record reached 4 inches.
How hail size is reported
Most sizes in the NOAA record are estimates made by comparing a stone to a familiar object: the reason the size chart above is organised around coins, balls and fruit. Measured stones are the minority. A report of "golf ball" becomes 1.75 inches in the database because that is the conventional conversion, not because anyone put a caliper on it.
This matters when reading any hail statistic, including the ones on this site: the precision of the numbers is lower than the decimal places suggest. Treat 1.75 in and 1.80 in as the same thing.
Protecting a roof or a vehicle
Hail resistance is rated by UL 2218 in four classes, from Class 1 (the least resistant) to Class 4, which is tested against a 2-inch steel ball. Class 4 shingles reduce damage from moderate hail but are not hail-proof, and no shingle survives a 4-inch stone intact. For vehicles, covered parking is the only reliable protection; hail blankets and mats help against smaller stones.