Last Day Summer 2025. Thursday, june 20 is the official first day of northern astronomical summer for 2025 — summer solstice — which is the longest day of the year for this half of the. What is the summer solstice?
Although some consider summer’s end to be labor day or when the kids go back to school, the official last day of summer for 2025 is september 22. The summer solstice happens on thursday, june 20, 2025!
