Although meteorological summer and the 2025 Atlantic hurricane season both began already, on June 1, another measuring stick for summer’s arrival will come this weekend.
This Friday, June 20, is the summer solstice, the longest day of the year in the northern hemisphere and the astronomical start of summer.
Here’s what to know about the summer solstice and when it last fell on June 22 — the rarest date for the longest day (it won’t fall on June 22 for another 178 years).
What is the longest day of daylight in 2025?
Every year in June, the summer solstice marks the exact time when the sun reaches it northernmost point in the sky, according to EarthSky. In the Northern Hemisphere, the June solstice marks the shortest night and longest day of the year.
The sun’s actual moment of reaching its northernmost point will be at 10:42 p.m. ET Friday, June 20.
Is June 21 always the summer solstice?
No, the summer solstice doesn’t always fall on the same calendar date.
“The date of the equinoxes and solstices varies because a year in our calendar does not exactly match the length of the tropical year — the time it takes the Earth to complete an orbit around the sun,” according to timeanddate.com.
The summer solstice falls between June 20 and June 22 and the specific date depends on when the sun reaches its northernmost point from the equator, according to the Farmers’ Almanac.
June 22 solstices are rare, according to timeanddate.com. The last June 22 solstice was in 1975, and there won’t be another one until 2203.
When is the first day of summer 2025?
The first day of summer depends on which summer you’re referring to. There’s meteorological summer, which runs from June through August.
There’s also astronomical summer, which runs from the summer solstice to the autumn equinox. In 2025, that means astronomical summer will be from June 20 through Sept. 22.
What day does summer technically start, end? Difference between meteorological and astronomical seasons
Astronomical seasons are marked by equinoxes and solstices, which relate to the position of the earth. Meteorological seasons are based on annual temperature patterns and cycles, which is why each season has both an astronomical and meteorological first day.
“Astronomical seasons are based on the position of the Earth in relation to the sun, whereas meteorological seasons are based on the annual temperature cycle,” NOAA says.
“The Earth’s annual trip around the sun forms the basis for the astronomical calendar in which seasons are defined by two solstices and two equinoxes.”
According to Accuweather, meteorological summer is exactly three months long. It began on June 1 and lasts through August 31 every year. This year, the meteorological start of the summer landed on Sunday, June 1, 2025.
The astronomical start of summer – which is marked by the summer solstice each year – is still yet to come, falling on this Friday, June 20.
When are 2025 solstices and equinoxes?
This article originally appeared on Treasure Coast Newspapers: When is summer solstice 2025? What to know about the longest day of the year in 2025
Reporting by Lianna Norman and Cheryl McCloud, USA TODAY NETWORK – Florida / Treasure Coast Newspapers
USA TODAY Network via Reuters Connect
