Summer Solstice 2025: When is it, what it means, and why it’s the longest day of the year

The Summer Solstice 2025 in the Northern Hemisphere will occur on Friday, June 20, 2025, at 10:42 PM EDT (0242 GMT on June 21). This astronomical event marks the start of summer and the longest day of the year in terms of daylight hours.

What is the Summer Solstice?

The summer solstice happens when Earth’s North Pole is tilted closest to the Sun, causing the Sun to appear at its highest point in the sky. As a result, regions in the Northern Hemisphere enjoy extended daylight, early sunrises, and late sunsets.

Derived from the Latin solstitium (“sun stands still”), the word “solstice” refers to the point at which the Sun’s apparent motion in the sky pauses before reversing direction. Ancient civilizations, such as those who built Stonehenge, monitored this solar milestone to track time, seasons, and spiritual significance.

When is the Summer Solstice 2025?

Date: June 20, 2025

Time: 10:42 p.m. EDT / 0242 GMT (June 21)

Hemisphere affected: Northern Hemisphere (start of summer); Southern Hemisphere (start of winter)

Why it happens

Earth orbits the Sun on a tilted axis — about 23.5 degrees. During the solstice, the Northern Hemisphere receives sunlight at the most direct angle of the year, while the Southern Hemisphere enters winter, experiencing its shortest day and longest night.

At the exact time of the solstice, the Sun stands directly over the Tropic of Cancer, an imaginary line located 23.5 degrees north of the equator. From this moment forward, the Sun’s path begins to move southward.

What to expect

In the Northern Hemisphere, the solstice brings early dawns, long days, late sunsets, and short nights. For skywatchers, the Sun appears to rise and set at its most northerly points on the horizon, with the noon Sun appearing highest in the sky compared to any other day of the year.

Cultural and scientific significance

Many cultures celebrate the solstice with festivals and rituals, embracing the symbolic shift toward abundance, light, and growth. Scientifically, the solstice marks a turning point — from this day forward, daylight hours will begin to slowly decrease until the winter solstice in December.