The longest day of the year is the day with the most hours of daylight, which occurs on the summer solstice. In the Northern Hemisphere in 2025, this day falls on June 21. The duration of the longest day varies by location, but for example, in Amsterdam on June 21, 2025, the longest day lasts approximately 16 hours and 48 minutes from sunrise to sunset. Near the poles, such as in the Arctic Circle, the longest day can be 24 hours long with the phenomenon of the midnight sun, where the sun does not set at all.
Key points about the longest day:
- The exact length of the longest day depends on the latitude.
- At mid to high latitudes, the longest day is around 16 to 17 hours.
- Near the poles, the longest day can be continuous daylight (24 hours).
- The summer solstice occurs when Earth's axial tilt is maximally inclined toward the Sun, making the Sun appear highest in the sky.
Therefore, the longest day of the year can range from about 16-17 hours of daylight at mid-latitudes to a full 24 hours of daylight near the polar regions.
