The Hami melon (哈密瓜) is one of the most celebrated agricultural products in China, and visiting Hami in the harvest season (July to October) gives you the opportunity to eat it at source in a way that supermarket versions in Chinese cities cannot replicate. The peak-season melons are large, golden-skinned, white-fleshed, and intensely sweet — the combination of the oasis basin's mineral-rich soil, intense summer sun, and cold desert nights produces a sugar content that is difficult to match elsewhere.
The main market for melons is the Hami bazaar, where farmers bring their harvest on carts and sell by weight. Prices are low compared to anywhere else in China. The variety sold in markets across the rest of the country is typically a smaller version bred for transport; the full-sized local melons are considerably more impressive. If you are passing through by train, the station platform vendors also sell slices, and this is one of the genuinely justified local food traditions worth participating in.