St. Petersburg and surrounding areas experienced a display of noctilucent clouds on the night of June 4th. These rare atmospheric phenomena, also known as polar mesospheric clouds, were spotted, marking an early and extensive appearance for the year.

Noctilucent clouds are a summertime occurrence. They form at altitudes of 70–95 kilometers due to a specific combination of factors.

The formation process requires a sufficient amount of water vapor present in the upper atmosphere. Extremely low temperatures at these altitudes are also crucial.

Finally, the presence of tiny dust particles, often believed to be of meteoric origin, is needed. Water vapor condenses on these particles, forming ice crystals.

The characteristic bluish-silver glow of noctilucent clouds comes from sunlight scattering off these ice crystals.