Residents in the small Arizonian town of Snowflake were treated to a bright purple display in the night sky as a result of the ultraviolet lights used at a local medical marijuana farm.

A photo taken by resident Cara Smith revealed the stunning spectacle on social media, where the image went viral.

The phenomenon was a result of ultraviolet lights used on the farm reflecting off the snow on the ground and lighting up the clouds in the sky, explained the Weather Channel.

Water droplets in the atmosphere at the time helped disperse the light and spread it across the sky.

Ms Smith took the photo at 6.30am on Friday from her home, two miles west of Copperstate Farms.

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She told CNN the purple lights are usually not visible from her home and “don’t usually light up the sky like this”.

“It had snowed that morning and was still very foggy and cloudy,” she added.

Navajo County said: “The snow wasn’t the only gift the skies had in store for us this morning.

“This photo taken from Snowflake, AZ early this morning showcased purple glow for miles!”

Copperstate Farms has been in operation since 2017 and grows 70 strains of cannabis for medical use in 40 acres of greenhouses.