Summer Solstice 2025 Dates Uk. When is summer solstice 2025. The summer solstice represents the longest day, and the winter solstice the shortest.
In 2025, the summer solstice will occur on june 21, at 02:42 gmt in the northern hemisphere, and on december 21, 2025 at 09:20 gmt in the southern hemisphere. It marks the longest day of the year and the arrival of the summer season