Summer Solstice 2025 Southern Hemisphere. When is the summer solstice 2023? Summer 2025 starts on friday, june 20th in the northern hemisphere, with the first day of summer being the longest daylight day of the year with the earth's axis.
As the sun reaches the northernmost point of its orbit, the summer solstice occurs in the northern hemisphere. 10:57 am edt, june 21: