Longest Day Of The Year 2025. In 2025 the summer solstice will occur on saturday 21 june at 03.42 bst (02.42 gmt). Sun mon tue wed thu fri sat;

In 2025 the summer solstice will occur on saturday 21 june at 03.42 bst (02.42 gmt). In other words, on june solstice it is summer time in the uk, the usa, canada, russia, india, and china and it is the longest day of the year while it is winter time in australia, argentina, chile,.