Every summer, one of the most ghostly sights in the sky quietly returns.
They’re called noctilucent clouds — literally, “night-shining clouds” — and they can look like glowing blue-white ripples, waves, or delicate brushstrokes suspended low in the twilight sky. They are not auroras. They are not ordinary weather clouds. And they are not something you can count on seeing every clear night.
That’s what makes them so special.
The 2026 noctilucent cloud season is now underway, with early sightings already reported from high northern latitudes, including a June 2 display photographed over Kennewick, Washington, and a May 31 report from northern Germany.
Clouds at the edge of space
Most clouds we see drift through the lower atmosphere, just a few kilometres above our heads. Noctilucent clouds are in a completely different league.
They form in the mesosphere, roughly 80 kilometres, or about 50 miles, above Earth — making them the highest clouds in our atmosphere. They are made of tiny ice crystals, and because they sit so incredibly high, they can still catch sunlight even after the Sun has dipped below the horizon for us on the ground. That’s why they seem to glow after sunset or before sunrise, while ordinary clouds below them appear dark.
Think of it this way: you are standing in twilight, but those clouds are still in sunshine.
That is the magic.
When should you look?
The best time to watch is during the summer twilight season, especially from late May through early August in the Northern Hemisphere, with June and July often offering the best chances.
Start looking about 40 minutes to two hours after sunset, low toward the northwest to northern sky. For the early risers, there is also a chance before dawn, looking toward the northeast, where the Sun will soon rise. NASA’s Space Cloud Watch project also recommends watching just after sunset or just before dawn from high-latitude locations.
For those of us in southern Canada we are near the southern edge of the usual viewing zone. That means displays may be lower, fainter, and less frequent than they are farther north, but they are absolutely worth watching for.
What do they look like?
Look for thin, electric-blue or silvery-white clouds that seem to glow against a deepening twilight sky. They often appear as:
wispy streaks, rippled waves, delicate bands, or bright bluish veils.
The key clue is contrast. Ordinary clouds near the horizon will look dark after sunset. Noctilucent clouds do the opposite: they shine.
A clear northern horizon helps a lot. Try a lakefront, open field, hilltop, or anywhere with an unobstructed view away from bright lights. You do not need a telescope. In fact, this is one of those rare sky events best enjoyed with just your eyes, a camera, and a little patience.
Why are they so mysterious?
Noctilucent clouds need a strange combination of ingredients: extreme cold, tiny ice crystals, dust particles high in the atmosphere, and just the right twilight geometry. Some of that dust may come from meteors, volcanic material, or even human-made sources such as rocket exhaust. NOAA notes that these clouds are rare because ice crystals do not easily form so high in the atmosphere, where water vapour and dust are limited.
Scientists are also watching them closely because their range appears to be changing over time. NASA’s Space Cloud Watch project is asking citizen scientists to report both sightings and non-sightings, because these observations may help researchers better understand changes in Earth’s middle atmosphere.
So this is not just a pretty sky show. It is also a window into a part of our atmosphere most of us never think about.
How to photograph them
A smartphone can work surprisingly well if the display is bright. Try resting your phone on something steady, turn off the flash, and use night mode if available. A wide view of the sky with a bit of landscape in the foreground can make the scene more dramatic.
For a DSLR or mirrorless camera, start with a wide lens, focus manually on a distant light or star, and try exposures of a few seconds. Keep checking your images because the brightness and structure can change from minute to minute.
And remember: these clouds can sneak up on you. One minute the sky looks ordinary. A few minutes later, faint blue ribbons may begin to appear.
The Night Sky Guy observing tip
My advice: after a clear summer sunset, don’t rush back indoors.
Give the twilight sky a second look.
Face north or northwest. Let your eyes adjust. Scan low above the horizon. If you see silvery-blue ripples shining where normal clouds should be dark, you may be seeing one of the most beautiful high-altitude phenomena on Earth.
Noctilucent clouds are subtle, rare, and unpredictable — but that is exactly why they are so rewarding. They remind us that the night sky is not only about stars, planets, and the Moon. Sometimes the atmosphere itself becomes part of the show.
So this summer, keep an eye on the twilight.
The sky may be glowing long after sunset.
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