Hail size chart: dime to softballs

Hail diameter reference

Approximate NWS glossary comparisons. This display is not a life-size ruler.

When does NWS call hail severe?

Hail at least one inch in diameter—commonly compared with a quarter—meets the hail criterion for a severe thunderstorm. A storm can also be severe because of wind; a lack of large hail does not make the storm safe.

The chart uses NWS glossary reporting comparisons. These are approximate diameter labels, not a calibrated ruler. Objects and local reference charts can differ, especially softballs. A measured diameter is more useful than an uncertain object comparison.

Does golf-ball hail cause damage?

Golf-ball hail is about 1¾ inches across, well above the severe threshold. Hail can damage roofs, vehicles and vegetation and injure people. Size alone cannot predict a repair bill or prove that a particular roof was damaged.

Wind, the number of impacts, hail characteristics and the condition of the surface all affect the outcome. A cover or other product should not be treated as a guarantee against hail damage. Move vehicles into sturdy shelter before storms arrive, only when safe.

Measure and document after the danger passes

Stay inside and away from windows during the storm. Wait until conditions are safe before taking photographs. Include a ruler beside the largest hailstone and record the time and location. Hail melts, so explain if your measurement was delayed.

Report observations through your local NWS office’s preferred channels. Do not climb onto a wet or damaged roof. For preparedness equipment, use the gear guide’s buying notes and check manufacturer limitations before a storm—not during a warning.

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