What Is The Longest Day Of The Year 2025 Uk. Bank holidays in england and wales 2025: The summer solstice marks the first day of summer in astronomical terms.
In 2025 the summer solstice will occur on saturday 21 june at 03.42 bst (02.42 gmt). A december solstice on the 23rd is once in a hundred years occurrence, and a december 20 solstice is even rarer.