noun
summer solstice
Refers to the yearly solar term around June 21 in the Northern Hemisphere, when daytime is longest; commonly contrasted with 冬至.
See also: 冬至
夏至の日は、一年で昼が最も長い。
On the summer solstice, the day is the longest of the year.
夏至を過ぎると、少しずつ日が短くなる。
After the summer solstice, the days gradually become shorter.
A Sino-Japanese compound written with 夏, 'summer,' and 至, 'arrival; reaching a point.' The spelling conventionally matches the idea of the sun reaching the summer solstice.