First Day Of Summer 2025 Usa Calendar. A day later, on june 21, the full moon will rise at 9:08 p.m. This is the longest day of the year and marks the start of summer in the northern hemisphere.

Hope you’ve got your pencils ready and your calendars out: Here’s a list of the exact dates and times of the four seasons in north america, including the first days of winter, spring, summer, and fall for the next few years.