Strange ‘Space Clouds’ Seen Glowing Across Northern Hemisphere

Noctilucent clouds, also known as night clouds, are seen above the capital Tallinn, Estonia, early Friday, July 17, 2026. (AP Photo/Sergei Grits)

Copyright 2026 The Associated Press. All rights reserved

Skywatchers across northern Europe are once again reporting spectacular noctilucent cloud displays, with brilliant electric-blue formations illuminating the late-night sky as one of the season's celestial highlights. According to SpaceWeather.com, observers have been photographing the rare “night-shining” clouds across the region. The latest displays come as the annual noctilucent cloud season reaches its peak, when summertime water vapor rises into the mesosphere and freezes onto tiny particles of meteor dust at the edge of space. That meteor dust comes from the Perseid meteor shower, among other displays of “shooting stars” this summer.

The glowing displays mark the return of one of summer’s most beautiful and unusual astronomical phenomena. Here’s everything you need to know about noctilucent clouds — and when to see them from the northern U.S.

What Are Noctilucent Clouds?

Often referred to as “night-shining clouds,” noctilucent clouds are the highest clouds in Earth’s atmosphere. They form around 47 to 52 miles (76 to 85 kilometers) above Earth’s surface in the mesosphere, a region close to the boundary between the atmosphere and space.

Unlike ordinary weather clouds, noctilucent clouds consist of tiny ice crystals that form in temperatures as low as -184 degrees Fahrenheit (-120 degrees Celsius). Those crystals develop around microscopic dust particles left behind when meteoroids burn up high above Earth, creating the shimmering blue and silver patterns visible after sunset.

Because they exist at such extreme altitudes, the clouds remain illuminated by the sun long after darkness has fallen at ground level, giving them their distinctive glowing appearance.

Why Noctilucent Clouds Appear During Summer

Although they are made of ice, noctilucent clouds are primarily a summer phenomenon. During the Northern Hemisphere summer, water vapor rises into the mesosphere, where temperatures are cold enough for ice crystals to form. Combined with the constant supply of meteoric dust, these conditions create the perfect environment for noctilucent clouds.

Displays are most common between late May and early August, with June and July generally offering the best viewing opportunities for observers at about 50 to 70 degrees north latitude, placing much of Alaska, central and northern Canada, and northern and central Europe in the prime viewing zone.

How, When And Where To See Noctilucent Clouds

The best time to look for noctilucent clouds is about 60 to 90 minutes after sunset or before sunrise, when the sun is just below the horizon but still illuminates the high-altitude ice crystals.

Look low toward the northern horizon under clear skies. The clouds often appear as delicate, rippling bands glowing in electric blue, silver or white. No special equipment is required, although binoculars can reveal additional detail in their intricate wave-like patterns.

While noctilucent clouds are most commonly seen across northern Europe, Canada and Alaska, observers in the northern U.S. — including parts of Minnesota, Michigan, Wisconsin, Montana and New England — have also reported displays in recent years during especially favorable conditions.

Wishing you clear skies and wide eyes.