Like most travel destinations, the most popular time to take a vacation to China is in the warm summer months. As tourism in China continues to grow in leaps and bounds, the best places to go when visiting China tend to get smothered by tourists between June and September, particularly at the amazing historic attractions such as the Great Wall of China. Hotel prices rise. Food and drink prices rise. Prices for train travel rise. This should be nothing to new to even a novice traveler, and China is certainly not immune to grabbing the tourist dollar.
A vacation to China can be a relaxing one, an adventurous one, or a spiritual one. If you are looking for relaxation, that is mostly found in the southern areas of the country. Guangdong, Hainan, and Yunnan are the best places to go when visiting China. With regards to these locations, it matters less when you go—the temperatures are mild to hot year round, and spring is the best if you want to beat out not only the foreign tourists but also the thousands of Chinese who head to these regions during their summer vacation too. You may wish to avoid the rainy season, too, which begins in May. The same holds true for the autumn months—many people will have cleared out by the time you arrive. Macau and Hong Kong are, of course, exceptions. They are two of the most popular places to go when visiting China, so regardless of the time of year, there are always huge crowds everywhere. The first of many China travel tips when trying to avoid crowds in these cities is: it's really, really not worth your time to try. The only way is to hole up in your hotel room, and that's no fun for anyone. Still, the winter is slightly less cluttered and busy, not counting the country's biggest holiday.
This is the one day to look out for: Chinese New Year. Number one of China travel tips: don't even consider trying to get anywhere on this day—you will get nowhere. It's best to just grab a seat somewhere and enjoy the show. You have little other choice.
Be careful if taking a vacation to China in the winter—primarily the northern parts of the country. These regions can get so cold it's hard to form complete sentences when you talk. Not only that, but many of the lodgings also shut down for the winter, making accommodations a little more difficult to come by, which doesn't sound so bad until you are wandering around the outskirts of Harbin in early January without a place to stay.
One problem with traveling during the Chinese summer is occasional rainstorms and flooding. One of the main China travel tips is to keep in mind the onset of the rainy season. It begins during the middle of spring, and from then on the weather can be particularly volatile. Primarily in the southern parts of China, where monsoons and typhoons are sometimes an unwelcome addition to one's trek through the country. But you shouldn't worry too much about these phenomenon; it's clear, when traveling through the popular regions to the south, that few others do.