What is the longest day in a year in Taiyuan?

Don't you know geography? It should be the longest day in the northern hemisphere, that is, the summer solstice, that is, 6.22 or 6.23 (yellow calendar), and the daytime in the Arctic Circle can reach 24 hours. In the southern hemisphere, the day is just the opposite, and the day is the shortest. Generally, you can't ask Taiyuan or which area.