When Does Summer Start 2025. 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. Aug 25 to aug 27, 2025:
Discover why itโs important to know when summer 2025 will start and how to plan ahead for agricultural and recreational activities. The university of texas at arlington’s official academic calendar for past and current semesters.