What is the longest of the 24 solar terms in a day?

Summer solstice: Beidou points to B. The meridian of the sun is 90 degrees. When the sun is at the "Summer Solstice Point" at 90 degrees of the yellow meridian, it is almost directly above the Tropic of Cancer, and the sun is the highest in the northern hemisphere at noon. This day is the longest day and the shortest night in the northern hemisphere. From this day on, it entered the hot season, when everything in the world grew most vigorously. In ancient times, the heart also called this day the northern solstice, meaning the northernmost day when the sun was born. After the summer solstice, the sun gradually moves southward, and the days in the northern hemisphere become shorter and the nights become longer.