Bring on the cookouts, bust out the outdoor games, and start filling up those stock tank pools …summer is just about here! Though temps have been steadily rising across the country for weeks now, you may be surprised to know that the season of fresh watermelon, breezy beach reads, and long weekend getaways to quaint small towns doesn’t officially kick off until just about halfway through the year. So when is the first day of summer, exactly? Read on for everything to know about kicking off the season right, including the celestial matters that dictate the transition from spring.
When is the first day of summer?
In the northern hemisphere this year, the first day of summer is Thursday, June 20, 2024. That’s just after Father’s Day and Juneteenth—so we recommend keeping the celebration going.
What determines the first day of summer?
The first day of summer is determined by the tilt of the earth's axis as it rotates around the sun. The day that the North Pole is pointed closest to the sun, the northern hemisphere receives the most light for the longest amount of time. This day is known as the June or summer solstice, with a solstice being the twice-yearly astronomical occurrence when the sun is the greatest distance from Earth’s equator. (If you’re in the northern hemisphere, that means the sun will sit at its highest point in the sky during the summer solstice; during the winter solstice, it will sit at its lowest.)
As the 24-hour period with the longest “day” and shortest “night” in the 365-day calendar year, the day of the summer solstice marks the first day of the summer season. If you want to get really technical, the exact time of the summer solstice this year is 4:51 p.m. EDT—which means you might want to pour a cup of coffee while you ring it in.
Is it the same day every year?
Not exactly, and that is due to how long it technically takes the earth to complete one rotation around the sun. The Gregorian calendar, which is the international standard used for societal and scientific purposes, marks this passage of time—one year—as 365 days. But a solar year is actually closer to 365 days and six hours. This discrepancy gives us Leap Day every four years, and it also bumps the summer solstice a day or two depending on the year. The first day of summer will always fall on or between June 20 and June 22.
When does summer end?
In the northern hemisphere, the September or autumn equinox marks the end of summer and the beginning of fall. An astrological equinox, which occurs twice yearly, is the date when the sun passes over the equator, and from the northern hemisphere to the southern hemisphere. (On this date, day and night will be of equal length.) After the autumn equinox, the North Pole begins to tilt away from the sun, which begins a season of longer nights and shorter days. This year, the autumn equinox is Sunday, September 22, 2024. That means you’ve got about 94 days to make the most of summer this year—and we’ve got the perfect summer bucket list of warm-weather activities to get you started.
