First Day Of Summer 2025 Calendar Date And Time. — 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. Because the earth rotates on a tilt, the summer solstice takes place when the northern.
For those of us in the northern hemisphere, earth is. — 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.