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Weather explained: What are noctilucent clouds?

15:00
28 August 2022

Weather explained
What are noctilucent clouds?

Noctilucent cloudsNoctilucent clouds shine in the night sky over Tynemouth Priory and Castle in June 2022. - © picture alliance

Bright, shimmering noctilucent clouds illuminate the skies each year with a season spanning from May to August, here's how.

Known as noctilucent clouds, these rare clouds form around 50 miles above Earth’s surface in the mesosphere during summer months.

The unusual display of blue and silver ribbon clouds can keep the evening sky bright hours after the sun has set.

It is not known for sure how these clouds form, although we know that they shine thanks to the sun’s light illuminating ice crystals from beyond the horizon.

These crystals reflect the light onto dust particles in the mesosphere, where temperatures reach -134C.

Best viewed when the sun has just set below the horizon, 90 minutes after sunset, the clouds are most likely to appear between June and August for those of us in the Northern Hemisphere although their full season runs from May to August.

If you spot any bright shining clouds at night in the coming months, we would love to see them!

Snap a picture and submit by tapping the image icon in our app or use the dedicated picture uploader.

Weather & Radar editorial team
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