What should I wear to Chagan Lake in Jilin in early June?

Boys wear half-sleeved trousers and girls wear skirts. Jilin is located in the middle of the northeast plain of China. It was hot in early June, and I was going to take photos in Chagan Lake, so boys wore half sleeves and half legs, while girls wore skirts. Chagan Lake is located in the former Guoerluosi Mongolian Autonomous County in the northwest of Jilin Province, bordering Gan 'an County in the west and Da 'an City in the north.