Summer Solstice May Reveal Rare Electric Blue Clouds In Northern Hemisphere

IN FILE - Noctilucent clouds, also known as night clouds, are seen from the village of Negnevichi, 140 kilometers (459317.6 feet) (87 miles) west of Minsk, Belarus, late Tuesday, July 21, 2020. Noctilucent clouds are thin and forming high above the Earth at heights of 70-90 kilometres, so they can only be seen at twilight, shining after the sunset. SERGEI GRITS/AP PHOTO

The longest day of 2023 is about to unfold for the Northern Hemisphere, and after the sun finally sets, skywatchers in certain areas of the globe might be able to spot a type of cloud that goes undetected throughout the rest of the year.

The summer solstice occurs every year between June 20 and June 22 in the Northern Hemisphere when the sun is directly over the Tropic of Cancer. As the Earth orbits around the sun on its axis, the most direct rays from the sun migrate southward, eventually reaching the Tropic of Capricorn on the winter solstice between Dec. 20 and Dec. 22.