When Is The First Day Of Summer 2025 Solstice. To visualize the time period between a given start date and the summer solstice of 2025 (june 20th, for this example), a calendar is useful. 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 having reached its furthest tilt and begins to change.

12 rows the dates of summer solstice / summer for the next 10 years: Summer solstice 2025 will take place on june 21st, but in 2025 the summer solstice will take place on june 20th.