A rarely seen cloud iridescence has appeared briefly above a small Wheatbelt town, delighting residents lucky enough to catch a glimpse of the colourful optical phenomenon.

Jenni Shaw was at her family owned business in Goomalling, 130 kilometres north-east of Perth, when a staff member received a text message instructing them to look at the sky.

“We all went out the front and had a look and there was some bright, rainbow-type clouds in the sky that we hadn’t seen before,” she said.

“But we were a bit like ‘why is that like that? Should we still be outside looking or not?’.”

A Goldilocks moment

Jessica Lingard from the Bureau of Meteorology said rainbow clouds, known as cloud iridescence, form in the same way as rainbows; when sunlight diffracts off water or ice crystals in the sky.

“It’s quite a rare phenomenon to catch in person,” she said.

“It’s the perfect storm of conditions: the sun’s at the right angle, the clouds are not too thin and not too thick that they’re being blocked out, and the sunlight has just created this spectacle of coloured light.

Ms Lingard said cloud iridescence was likely “as common” as rainbows.

But what makes spotting rainbow clouds so rare is that they can disappear as quickly as they appear.

“Rainbows tend to last a little bit longer. These ones can be trickier to spot,” she said.

“They really only last five or 10 minutes and then the conditions change.”

Ms Shaw said the rainbow-coloured cloud was visible for just a few minutes.

“It was not there long, just long enough for us all to get some photos,” she said.