The summer solstice in 2025 falls on Friday, June 20. It occurs at 10:42 p.m. Eastern Time (EDT) in the United States, which corresponds to June 21 at 02:42 UTC. This marks the longest day of the year and the official beginning of astronomical summer in the Northern Hemisphere. In some regions like the UK and Europe, due to time zone differences, the solstice is observed on June 21. The event occurs when the Sun is directly over the Tropic of Cancer, resulting in the longest daylight period of the year for the northern half of the globe. So, the key day to remember is June 20, 2025, for the Northern Hemisphere summer solstice. It is the first day of summer and the day with the most daylight.