also: みずかみなり
noun
thunder with rain; rain thunder
Refers to thunder that occurs together with rain, as opposed to dry thunder. A somewhat literary or traditional term.
水雷が鳴り響き、激しい雨が降り出した。
Rain thunder rumbled and a heavy rain began to fall.
noun
lightning without fire; non-igniting lightning
Lightning that does not start a fire, often associated with rain. Compare with 日雷 (ひがみなり), which is dry lightning that can cause fires.
See also: 日雷 (ひがみなり)
水雷は火事を起こさないので、少し安心だ。
Since rain lightning doesn't start fires, it's a little reassuring.
Irregular okurigana variant of 水神鳴り.
Alternate reading; less common than みずがみなり.
日雷 is dry lightning that can cause fires, while 水雷 is lightning accompanied by rain that typically does not start fires.
Compound of 水 (みず, water) and 雷 (かみなり, thunder/lightning), literally 'water thunder'. The reading みずがみなり uses the older combining form がみなり for 雷.