The name Rainhailorshine has proven a little too apt for a Waikato racehorse, struck dead by a bolt of lightning.

Cambridge trainer Ralph Manning went out to check on his animals on Wednesday morning and found the 6-year-old brown gelding lying dead in a paddock.

Mr Manning said a really big storm struck on Tuesday night and the horse had been hit by lightning.

The trainer, who had a half-share in Rainhailorshine, was shocked by the way he died. "It's pretty unique, pretty unusual."

Rainhailorshine had two wins, two seconds and four thirds from 24 starts - earning a total of $17,350 - and was returning to form after a spell.

Waikato Racing Club chairman David Smith, who owned a quarter-share, said Rainhailorshine would be missed.

"He was a fun horse without being a top-liner," Mr Smith said.

Rainhailorshine was true to his name and liked the outdoors, he said.

"He was a big horse and didn't like the confines of the boxes."

Unlike most thoroughbreds in New Zealand, he spent his nights in a paddock, rather than stables.

Mr Smith said deaths from horses taking fright and running into fences in storms were not uncommon, but neither he nor New Zealand Thoroughbred Racing could recall a horse being killed by lightning.

Deaths have been reported in Kentucky, where horses tend to sleep outside and electrical storms are frequent.