Noctilucent Clouds

Noctilucent clouds are my favourite cloud.

These water ice clouds are the Earth’s highest, forming at 50-80km altitude in the mesosphere. They are visible between 50-70° north and south a few weeks around the summer solstice when the mesosphere is cold enough for them to form. They are only visible during the long twilight hours after sunset and before sunrise, when the lower layers of the atmosphere are in Earth’s shadow, but these high-altitude clouds remain lit by the Sun. These rare clouds shine a brilliant electric blue, often forming into mesmerising bands and waves, and bring an ethereal beauty which shines down on the quiet world below.