Summer Solstice 2025 Date Us. The summer solstice is also known as the longest day, which is perhaps the most notable feature. Daylight saving time starts at 2 a.m.
In 2025, the summer solstice in the northern hemisphere will occur on june 20, 2025, at 10:42 pm edt (or 2:42 am utc on june 21). This is the longest day of the year and marks the start of summer in.