Solar panels are rated against hail impacts as a condition of certification, and most storms pass over an array without leaving a mark. The damage that does occur is frequently invisible from the ground, which is the part worth understanding.
This covers what panels are built to withstand, what actually breaks them, and how to check afterward. Our note on how long solar panels last covers normal aging.
Quick Answer
Panels sold to standard certifications are impact rated with ice balls at speed, and ordinary hail rarely damages them. Large hail can crack the glass or create microcracks in the cells beneath it, and the second kind reduces output without being visible.
Key Points
- Certification testing uses ice balls fired at panels at speed.
- Most hail events cause no damage at all.
- Microcracks reduce output without visible damage.
- Steeper tilt reduces the force of a direct strike.
- Production data reveals damage that inspection misses.
What Determines the Outcome
| Factor | Effect |
|---|---|
| Hail diameter | The dominant variable |
| Impact angle | Glancing blows do less |
| Panel tilt | Steeper deflects more |
| Glass thickness | Varies between products |
| Existing microcracks | Prior damage compounds |
| Frame and mounting | Flex transfers stress to cells |
Panels Are Impact Rated
Hail resistance is not left to chance. International certification standards include an impact test where ice spheres are fired at the panel surface at speed.
Panels sold through reputable channels carry these certifications, which is one practical reason to check for them rather than buying on price alone.
Tempered glass is used precisely because it handles impact far better than ordinary glass and fails in a safer way when it does break.
That standard represents a specific severity rather than a guarantee, so exceptional hail can exceed what any panel was designed for.
What certification does establish is that routine hail is a non-event for a properly manufactured panel. Our note on panel efficiency covers what else the specification sheet tells you.
Two Kinds of Damage
Visible breakage of the glass
Obvious on inspection, and the panel needs replacing.
Microcracks in the cells beneath
Invisible from outside, and output drops quietly.
Damage to the frame or mounting
Less common, but affects everything above it.
Junction box or wiring damage
Rare from hail itself, more likely from wind-driven debris.
Microcracks Are the Real Concern
The damage worth understanding is the kind you cannot see, because it produces no obvious sign and reduces output permanently.
Silicon cells are brittle, and an impact that leaves the glass intact can still fracture the cell beneath it.
A cracked cell may keep conducting initially and degrade over subsequent months as thermal cycling widens the fracture.
Because panels in a series string share current, a degraded panel pulls down the whole string rather than only losing its own output.
This is why production data matters more than a visual inspection after a severe storm. Our note on panel orientation and output covers what normal production looks like.
Tilt Changes the Impact
The angle a panel sits at affects how much force a falling hailstone delivers.
A flat panel takes a direct perpendicular hit, transferring the full impact into the glass.
A tilted panel takes the same stone at an angle, so part of the energy goes into deflecting it rather than into the surface.
This is one of several reasons flat mounting is generally discouraged, alongside poor drainage and dirt accumulation.
Ground mounts have an advantage here, since their tilt can be chosen freely and some can be steepened when severe weather is forecast. Our roundup of tilt mounts covers adjustable options.
Age Compounds the Risk
An older array is more vulnerable than a new one, and not because the glass weakens.
Panels accumulate small stresses over years, from thermal cycling, wind loading and any handling during installation or maintenance.
Microcracks that already exist can propagate under an impact that intact cells would have absorbed.
This is why two identical arrays in the same storm can come out differently, and why history matters when assessing damage.
It is also an argument for careful handling at install, since damage introduced on day one sits there waiting for a reason to spread.
Checking an Array Afterward
A visual check is worth doing and is not sufficient on its own.
Look for cracked or shattered glass, dents in frames, displaced mounting hardware and damage to visible wiring or junction boxes.
Then compare production against what the array was doing before the storm, on a similar day. A drop with no visible cause points at cell damage.
String-level or panel-level monitoring narrows it down quickly, since a single underperforming string localizes the problem.
Do not walk on panels to inspect them, since that is itself a common cause of microcracks. Our roundup of panel cleaning brushes covers reaching an array safely.
What Else a Storm Damages
Hail arrives with wind, and the array is not the only thing exposed.
Mounting hardware takes the load a storm puts on the panels, and loosened bolts or bent rails are worth checking even where the glass is fine.
Wind-driven debris does more physical damage than hail in many storms, and a branch does things ice does not.
Wiring runs between panels are exposed, and a cable pulled or chafed during a storm becomes an intermittent fault later rather than an obvious one.
Ground mounts sit where debris collects and where flooding is possible, both of which matter more than the panels themselves. Our roundup of mounting kits covers the hardware.
Insurance and Warranty
Hail damage sits in a different category from a manufacturing defect, and the two are covered by different things.
Manufacturer warranties generally exclude damage from external events, since the panel did not fail on its own.
Property insurance is the usual route for storm damage, and coverage varies considerably by policy and region.
Documentation helps in either case. Production records from before and after a storm establish a change that a photograph cannot.
Confirm your own policy rather than assuming, particularly for ground mounts, which some policies treat differently from roof-mounted equipment.
Photographing the array while it is undamaged gives you a baseline to compare against, and it costs nothing to do on a clear afternoon.
Common Mistakes to Avoid
Assuming that intact glass means no damage
Microcracks in the cells are invisible and reduce output permanently.
Checking only visually in the days after a storm
Production data compared against a similar day before the storm is the reliable test.
Walking on the panels in order to inspect them
Foot pressure is a common cause of the exact damage you are looking for.
Mounting them flat in a hail-prone area
A flat panel takes the full perpendicular impact. Tilt deflects part of it.
Recommended Reading
See our note on whether panels need servicing, our guide on choosing solar panels, our roundup of ground mount racking, and our note on whether panels work in winter.
Hail and Solar Panels FAQ
Can hail break solar panels?
Large hail can crack the tempered glass, though panels are impact rated during certification and ordinary hail rarely damages them.
What size hail is a problem?
Hailstone diameter is the dominant factor, and certification standards covers a specific severity. Exceptional hail can exceed what any panel was designed for.
How do I know if my panels were damaged?
Check visually for cracked glass and frame damage, then compare production against a similar day before the storm. Cell damage shows in the data, not the photo.
What are microcracks?
Fractures in the silicon cells beneath intact glass. They reduce output permanently and can worsen over months as the panel heats and cools.
Does panel tilt matter?
Yes. A tilted panel deflects part of the impact, while a flat one takes the full perpendicular force.
Will my warranty cover it?
Usually not. Manufacturer warranties generally exclude damage from external events, and storm damage typically falls to property insurance instead.
Should I cover my panels before a storm?
Rarely practical, and anything that traps heat or moisture against a panel creates its own problems. Adjustable ground mounts can sometimes be steepened instead.
Can one damaged panel affect the others?
In a series string, yes. Panels share current, so a degraded panel limits the string rather than only losing its own output.
