Thunder stones and elf bolts
Across Europe, polished stone axe heads found in fields were believed to be thunderbolts — physical pieces of the storm that had fallen from the sky. They were kept in houses as protection, because lightning was thought never to strike the same place twice, and a house that already held a thunderbolt had nothing to fear.
They were, of course, Neolithic tools. But the instinct is touching: people carrying the storm's own weapon as a shield against it.
Ringing out the storm
Church bells across Europe were rung against thunderstorms — a practice so common that bell inscriptions boasted of it: 'I break the lightning.' The ringers were in genuine danger; the bell tower was usually the tallest structure around, and wet bell ropes conducted.
The custom faded as lightning rods arrived, which tells you something honest about folklore: it fills the gap where protection is missing, and steps aside when protection arrives.
Oak, ash and thorn
The oak was the thunder tree — sacred to thunder gods from Zeus to Thor, and said to draw the lightning. The rhyme 'beware the oak, it draws the stroke' is one piece of tree folklore that accident statistics quietly support: oaks are tall, often stand alone, and are struck often.
Sheltering under any lone tree in a storm remains a genuinely bad idea, whatever its species.
Storm omens for events
Thunder on a wedding day was read two ways: a voice of blessing from above, or a warning to be heeded. As with most omens, people kept the reading that suited the day.
The modern reading is simpler. Thunder means lightning, and lightning means the outdoor part of the day pauses. No charm outranks that.
The rule that actually protects you
When thunder roars, go indoors. If you can hear thunder, you are close enough to be struck, and a substantial building or hard-topped vehicle is the only real shelter. Wait thirty minutes after the last thunder before going back out.
Enjoy the folklore — it is magnificent — and let the safety rule be the one piece of storm lore you actually follow.