Look out for Noctilucent Clouds

Night clouds or noctilucent clouds are tenuous cloud-like phenomena, visible in a deep twilight. They are made of crystals of water ice. They are most commonly observed in the summer months at latitudes between 50° and 70° north and south of the equator. They can only be observed when the Sun is below the horizon.

We are in the right place, at the right time to observe them this summer. Keep watching the skies.

They are the highest clouds in the Earth's atmosphere, located in the mesosphere at altitudes of around 76 to 85 kilometres. They are normally too faint to be seen, and are visible only when illuminated by sunlight from below the horizon while the lower layers of the atmosphere are in the Earth's shadow. Noctilucent clouds are not fully understood and are a recently-discovered meteorological phenomenon.

Their occurrence can be used as a sensitive guide to changes in the upper atmosphere - increasing frequency, brightness and extent is possibly connected to climate change.