How Many Days Until Summer? 2027 Solstice Countdown

The longest day of the year

North of the tropics, which covers the 48 contiguous states and Alaska, the solstice day brings the most daylight of the year. After it, the Sun’s noon path drifts south again and the days shorten, slowly at first. The shortest day comes six months later, and the winter solstice countdown runs to it.

Meteorological summer starts June 1

Weather services count summer as June, July and August: 92 days that begin nearly three weeks before the solstice. NOAA’s National Centers for Environmental Information (NCEI) uses those whole months because they follow the yearly temperature cycle and make one summer easy to compare with the next. Astronomical summer, the one this page counts to, runs from the June solstice to the September equinox.

Why astronomical summer is the longest season

Earth reaches aphelion, its farthest point from the Sun, in early July, and moves most slowly along its orbit there. Northern summer spans that slow stretch, so it outlasts the other three seasons; the figure under the clock gives the coming summer’s length to the hour. Distance doesn’t make it warm: NASA credits the 23.5-degree tilt of Earth’s axis, which leans the Northern Hemisphere toward the Sun in June.

South of the equator the same June solstice starts winter. Someone in Sydney or Buenos Aires waiting for summer needs the December solstice instead. After summer, the first day of fall is next.