Noctilucent clouds appear in the summer in the northern hemisphere, they are the highest clouds in the atmosphere.

With the arrival of summer in the northern hemisphere, noctilucent clouds, also known as 'silver clouds', make their appearance, shining with an electric blue intensity in the dark sky. These clouds, which form at altitudes of 80-85 km, are the highest in Earth's atmosphere and are visible about half an hour after sunset.

Observations of them began only in 1885, coinciding with the eruption of the Krakatoa volcano, and some researchers suggest that industrial pollution may have contributed to their formation. Additionally, climate change could influence the appearance of these clouds by altering temperatures in the upper layers of the atmosphere. The phenomenon continues to fascinate, being a rare and beautiful spectacle, with their season in the southern hemisphere starting in October.