First Day Of Summer 2024 Time. July was the first time in more than a year that the world did not. When is first day of summer in 2024 is thursday, june 20, and it lasts until sunday, september 22, inclusive.
When do the four seasons start in 2024—for spring, summer, fall, and winter? On that day, the autumnal equinox will occur, marking the beginning of fall.