2025 1st Day Of Summer. In the northern hemisphere, it always occurs around june 20 or 21. For the northern hemisphere, the official summer season starts on june 20 or 21, depending on where you live, with the arrival of the summer solstice.
What is the summer solstice? In 2025 the summer solstice will occur on saturday 21 june at 03.42 bst (02.42 gmt).