Summer is almost officially here. The first day of summer and the longest day of the year in the northern hemisphere, the summer solstice marks the point in the year where the sun reaches its highest point in the sky.
Summer Solstice Time and Date
The Summer Solstice 2018 occurs on Thursday, June 21, at 06:07 a.m. EST and 3:07 a.m. PST. The sun will rise at 5:25 a.m. EST in New York City and set at 8:30 p.m., giving 15 hours and 5 minutes of daylight, while in Los Angeles sunrise is at 5:42 a.m PST and sunset is at 8:07 p.m., giving 14 hours and 25 minutes of daylight. The further north you go, the longer the day, with daylight lasting 19 hours and 21 minutes in Anchorage, Alaska, and the sun never setting in Prudhoe Bay in far north Alaska.
At the same exact time it will be winter solstice in the southern hemisphere, which marks the first day of winter and the shortest day of the year, when the sun reaches its lowest point in the sky.
How Does Summer Solstice Work?
The Earth is actually the furthest it gets from the sun all year a couple of weeks after the northern hemisphere’s summer solstice, on Friday, July 6, 2018 at 12:46 p.m. EST. So why is it hotter in summer? That's because Earth is tilted on its axis, spinning at an angle of 23.5 degrees as it orbits the sun along a slightly elliptical path. During summer solstice, the northern hemisphere is tilted towards the sun, so it receives more sunlight. The sun also takes a longer path across the sky, increasing the length of the day and the intensity of the sun's light.
Summer Solstice Events
Although it's not a visual phenomenon, the summer solstice occurs in the early morning on the east coast of the U.S. That makes it possible to watch a summer solstice sunrise from anywhere with a low view to the eastern horizon. If you're in Manhattan, you could then visit Solstice in Times Square: Mind Over Madness Yoga, a day of free yoga classes to celebrate the longest day of the year and the beginning of the summer season. Classes begin at 7:30 a.m. EST and continue until just after sunset.
In the U.K., the Stonehenge monument — an UNESCO World Heritage Site — will be open to visitors. It's thought that this 5,000-year-old monument is aligned to the Summer Solstice because on this day (and a few days on either side) the sun rises above its Heel Stone. Thousands of visitors are expected.
Another event marking the longest day of the year in the northern hemisphere is the Harvard Museums of Science & Culture's Summer Solstice Celebration, where from 5 to 9 p.m. visitors can get free admission to four of its museums.
How the Winter Solstice Works
At its winter solstice, the northern hemisphere is tilted away from the sun, so it gets less sunlight and the sun takes a shorter path through the sky. It’s also lower in the sky, so its light is less intense. Consequently, the northern hemisphere cools down. The next winter solstice in the northern hemisphere is on Friday, December 21, 2018 at 5:23 p.m. EST. However, shortly after that, the Earth will be the closest it gets to the sun on Thursday, January 3, 2019 at 12:19 a.m.
What Are Solstices and Equinoxes?
There are two solstices and two equinoxes each year, each marking the end of one season and the beginning of another. These astronomical events separate the Earth's annual orbit of the sun into four distinct parts. The two equinoxes occur when the planet is halfway between the two solstice points, when the Earth's axis is at a sideways angle to the sun, so neither hemisphere is pointed towards or away from the sun.
The equinoxes signal the start of fall (September 23, 2018 in the northern hemisphere) and spring (March 20, 2019 in the northern hemisphere), and are the only two days of the year when the sun rises due east and sets due west.