Longest Day In The Year 2024. Longest day of the year 2024 in united states. In 2024, the summer solstice occurs on thursday, june 20.

Yesterday, thursday, june 20, at precisely 20:50 universal time (4:50 p.m. Today (june 20) the summer solstice — the longest day of the year in the northern hemisphere — will begin, and it will be the earliest solstice in 228 years.