It’s that time of year in the Netherlands: Spot the rare night cloud phenomenon

You may have already heard people raving about how beautiful the night sky has been these last few days, and it’s all because of the “night cloud” phenomenon. Did you miss it? Don’t worry, there’s a pretty big chance you’ll be able to see it in the coming weeks.

The right weather conditions

It’s precisely at this time of year that the shiny clouds become visible - close to the longest day of the year - but, of course, certain weather conditions are needed for them to appear. You don’t just need a clear sky; it also needs to be cold enough at about 80 to 85 kilometres high in the sky for tiny ice crystals to form on dust particles.

The night clouds, also called Noctilucent clouds, appear to shine and produce light, but this is actually just sunlight being reflected down to the earth’s surface by the ice crystals. Being so high up, they are actually the highest clouds in the earth’s atmosphere. Passenger planes fly at about 12 kilometres high, so not at all close to these clouds!

See these shiny clouds

Only when the sun has set will you be able to see this rare phenomenon, which looks like silvery-blue streaks across the sky. These clouds don’t stick around for long either; you’ll likely be able to see them an hour after sundown and an hour before sunrise. Sometimes, you can see them the whole night, but more often than not they’ll only be visible for a short period of time.

To see them, make sure you look up to the sky on a clear day just after sunset. Be sure to look to the northeastern and northwestern horizon, and who knows, you may be lucky enough to spot this phenomenon.