What to Do During a Thunderstorm — the Complete Safety Guide

If less than 30 seconds pass between the flash and the thunder, the storm is within lightning-strike range — take shelter immediately. After the last thunder, wait another 30 minutes before returning to open ground — lightning can strike as far as 15 kilometres ahead of and behind a storm front, long after the rain has stopped.

Sound travels at about 340 metres per second — 3 seconds between the flash and the thunder is roughly 1 kilometre to the strike. It's a fast, practical way to judge how close a storm is without checking your phone.

Safe: a solid, built structure, a car with the windows closed (the metal body conducts current around the outside — the so-called Faraday-cage effect; plastic parts won't protect you, but the body itself does).

Dangerous: open ground (a field, a beach, a hilltop), a single tall tree (lightning strikes the highest point around, and a side flash can jump from the tree to someone standing nearby), an open-sided shelter or gazebo, swimming pools and water in general, metal fences and structures.

If you're caught in the open with nowhere to shelter: avoid being the highest point around, stay away from lone trees and metal objects, and if you feel the hair on your arms stand up (a sign of an imminent strike) — immediately crouch down, feet together, head tucked, minimising your contact with the ground to a single point. This isn't full protection, just risk reduction when you have no other option.

Driving during a storm, the biggest danger usually isn't lightning but sudden loss of visibility and hydroplaning on a flooded road. Slow down, use hazard lights in very poor visibility, don't stop on the shoulder of a main road (risk of being hit from behind) — pull into a car park or petrol station instead.

If a hailstorm is already close: stop somewhere safe and wait it out — driving into hail at speed risks cracking the windscreen. Don't park under trees — strong wind during a storm regularly snaps branches and topples trees onto parked cars.

Mountains: mountain storms build quickly, often in the afternoon, when heated slopes release heat intensely. When planning a route, check the morning forecast and come down from ridges and summits before midday — ridges and summits are the highest points around, exactly where lightning strikes.

Camping: a tent offers no lightning protection — fabric and poles provide no insulation. If a car or building is nearby, move there for the duration of the storm. Avoid pitching a tent under lone trees or on high ground.

Water: water conducts electricity far better than air, and a boat (especially one without a cabin) offers no protection. At the first signs of an approaching storm (darkening sky, a sudden pickup in wind) head back to shore — don't wait for the first thunder.

Even without a full lightning protection system, a surge-protected power strip for electronics is worth having — a surge from a nearby strike can jump across the power line, not just from a direct hit on the building. The safest option is simply to unplug sensitive equipment (computer, TV, router) during a strong storm.

These rules are universal, but the situation in your area changes hour by hour. This site's storm tool shows what time a storm cell is due to reach a chosen town, how long it will last, and which direction it's coming from — and if you're travelling in Germany, take a look at our storm alert for Germany with a link to official DWD warnings.

Official, binding warnings for the whole of Europe are published by MeteoAlarm — the joint system run by national meteorological services. That is the source to check for binding information, not just a model forecast.