Residents of an island in Queensland's Gulf of Carpentaria say a rare formation of clouds known as Morning Glory have appeared much earlier than expected.

Tex Battle from Sweers Island says the clouds, which appear like a roll of clouds in the sky, are usually visible from mid September.

He says the first formation appeared on Sunday and yesterday's clouds also brought some rain.

"It approached slowly, it was well formed, neatly formed and for the first time ever we had some rain come out of it - not much, just a trace," he said.

"I've never seen that before. It was only a trace, probably not enough to wet your shirt, enough to form a rainbow.

The Morning Glory cloud formation dominates the skyline over Sweers Island yesterday. ( Audience submitted: Sarah Martin )

"We've got photos of the rainbow.

"Sometimes you get the odd one at some unusual times of the year, but it will only ever be one.

"This has been two in quick successions.

"There will still be more of them in September - all the glider pilots will turn up at Burketown, as per usual.

"There are sometimes 30 aircrafts in Burketown gliding the glories."