The best time to see noctilucent clouds is on clear nights between late May and mid-August, about 90 to 120 minutes after sunset or before sunrise. Sightings are most common during June and July.

Amateur astronomer Alan Dyer saw this beautiful display of noctilucent clouds on the evening of June 17, near Calgary. These rare clouds have been quite active this year, experts and skywatchers say.

Noctilucent clouds (NLCs), or polar mesospheric clouds, are breathtaking to see. And these are no ordinary clouds. They form in the highest part of our atmosphere, at an altitude of 80 kilometres.

Stunning photos show bioluminescent plankton off the Cornish coast – below the Milky Way. Richard Haynes, 58, captured the ...

The clouds, called noctilucent clouds, have historically been relegated to the poles. But during the 20th century, the clouds were wandering further south, between the 40th and 50th parallel.

This rare phenomenon isn't as rare as it used to be. Eerily beautiful clouds glowing in the twilight sky are having a banner season in 2019. Noctilucent clouds (literally, 'night-shining clouds ...

Officially known as noctilucent, which is Latin for 'night-shining', these clouds occur only in the coldest conditions, because in the thin mesospheric air, ice crystals only form below -120°C.

Rain clouds tend to form no more than 10 miles up, but noctilucent clouds hover some 50 miles above the planet's surface in a layer of the atmosphere known as the mesosphere.

Northern lights and noctilucent clouds shining in Alberta skies, June 9. (Image credit: @TheAuroraGuy) Noctilucent clouds, northern light and comet Neowise captured on July 14, 2020.

With noctilucent clouds, as with the northern lights, the further north you are, the better chance you have at catching them. READ MORE: Rare, shimmering nighttime clouds on the rise, NASA says ...