Late April to early June. The annual harvesting period for open-air watermelons grown in Changle County, Weifang City is from late April to early June, when they are put on the market. Changle watermelon, a specialty of Changle County, Weifang City, Shandong Province, is a national geographical indication of agricultural products. The watermelon produced is famous for its early maturity, thin skin, crisp flesh and sweet taste. It is listed as one of the specialty fruits of Shandong Province.