What is the last day of summer?

The last day of summer in the Northern Hemisphere usually falls on September 21st, 22nd, 23rd, or 24th depending on the year. This day is also known as the <a href="https://www.wikiwhat.page/kavramlar/autumnal%20equinox">autumnal equinox</a>. It marks the transition from summer to autumn. During the <a href="https://www.wikiwhat.page/kavramlar/equinox">equinox</a>, the hours of daylight and darkness are nearly equal. After this day, the days gradually become shorter and the nights longer in the Northern Hemisphere, leading to cooler temperatures and the changing of leaves. People often celebrate the end of summer with festivals, outdoor activities, and preparations for the <a href="https://www.wikiwhat.page/kavramlar/fall%20season">fall season</a>.