When is the best tourist season in Yellowstone National Park?

Before May in Yellowstone National Park, many roads were closed and the weather was still cold. I went there in mid-May. It's not cold during the day, and the temperature is very low at night. At that time, the snow on the top of the mountain had not melted, and the scenery was good. The temperature is just right for hiking. If you go camping, you should bring enough clothes. Moreover, if you are unlucky, you may catch up with the snow. It is said that July-August is the peak season, and there are many tourists, because all campsites are open and students have time during holidays. Huangshi is not hot in summer, 25-30 degrees, and there are many good weather. But at this temperature, hiking may be a little hot. Because there were many tourists, there were relatively few animals at that time, and they were all scared away. Unless you walk into the mountains, it is estimated that you will not see rare animals on the roadside, but there will definitely be many big yaks. In fact, it seems that the end of May to the middle of June should be a good season. Moreover, there are few hotels in Yellowstone National Park, and people mainly camp in the park. It takes about 20 minutes to drive in and out of the park, and you can find a relatively dense hotel in a nearby town. Campsites need to be booked in advance, because it says that there are many people in summer and campsites are very popular, so it is inevitable that they will be booked out. Hotels are also more expensive in summer.