KanjiJLPT N1
Thunder

thunder, lightning bolt

Mnemonic

Heavy rain hammers an open field. Suddenly, a deafening crack of thunder shakes the earth beneath you! You're alone in the flat field as rain lashes your face—each rolling boom of thunder feels like the sky itself is splitting apart above you.
Additional thoughts
Picture a rice paddy (field) under dark storm clouds (rain). Thunder is literally rain above a field—the most exposed, dangerous place during a lightning storm. The flat openness amplifies every terrifying boom.
Quick recall
Rain hammers a flat field as thunder splits the sky above.

Details

The keyword for 雷 is thunder. This kanji represents the powerful natural phenomenon of thunder and lightning that occurs during storms. It conveys the idea of a loud, booming sound from the sky accompanied by flashes of light, and by extension can suggest something awe-inspiring, overwhelming, or terrifyingly powerful. In broader usage, it can also refer to anything that strikes suddenly and forcefully, much like a bolt of lightning.
On'yomi
らい
Kun'yomi
かみなり、いかずち、いかづち