It forms much higher than normal clouds, at about 85 kilometres above the Earth, as a result of ice packing onto particles of mainly meteoric dust high in the mesosphere. Because it is very thin, we cannot see it during the day and must wait for the sun to set, which illuminates it from below at dusk or dawn.

People can try to see the chilling beauty of the Noctilucent Clouds (NLC) in the following days. The visibility of NLCs this year is significantly affected by the high solar activity (maximum expected in 2025), so the high layers of the Earth's atmosphere do not have as stable conditions for the formation of NLCs as in previous years.Even so, conditions in the layers of the Earth's atmosphere where NLCs form, around 85 kilometres, could occasionally stabilise - especially on days when the Sun is not erupting in our direction.

Night clouds may now appear between 10pm and midnight, or between 2am and 4am, always in the north or between the northwest and northeast horizons. They do not shine by their own light, their glow being due to the scattering of sunlight which, at the hours in question, illuminates them from below (while they themselves are at a depth of between 6° and 16° below the horizon). They look like glowing spider webs in the sky and can sometimes offer a truly majestic spectacle.

If you don't want to miss the night clouds, we recommend that you monitor the webcams at the times indicated and go outside to observe them if they appear in the images. It is also advisable to sign up for alerts on this phenomenon. During the summer, other rare phenomena will also appear in the sky, we have prepared a list of them in a separate article. You can see all these phenomena while observing at our observatory WHOO! (White hole observatory Opava).

Contact details:

Mgr. Petr Horálek

RNDr. Tomáš Gráf, Ph.D.

Marián Runkas