Summer Solstice 2024 Longest Day In History. 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. This event, when the tilt of the earth's axis is most inclined towards the sun, results in the longest period of daylight in a day.

This event, when the tilt of the earth’s axis is most inclined towards the sun, results in the longest period of daylight in a day. 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.