First Day Of Summer 2025 Celebrations Party

First Day Of Summer 2025 Celebrations Party. 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 planet. The true solstice will arrive in the northern hemisphere at exactly 4:51.

But what is the first day of summer in 2025? Here’s how people celebrate the first day of summer around the world and whether it happens on the same day every year.