what is the longest day in the year

The longest day of the year is the **summer solstice**, which occurs around **June 20–21** in the Northern Hemisphere and around **December 21–22** in the Southern Hemisphere. On this day, the Sun reaches its highest point in the sky and daylight hours are at their maximum. In the Northern Hemisphere, the June solstice means places like London can experience around **16–17 hours** of daylight, while locations near the Arctic Circle can have nearly **24 hours** of continuous daylight (the "midnight sun"). The reason for this is Earth's **axial tilt** of about 23.5 degrees. As Earth orbits the Sun, this tilt causes one hemisphere to be angled more toward the Sun for part of the year, resulting in longer days and shorter nights during that period. The exact length of the longest day varies by **latitude** — the farther from the equator you are, the more extreme the difference between the longest and shortest days. At the equator, day and night remain roughly equal (about 12 hours each) throughout the year.