May and September through October are deemed the best times to visit China. Spring is adorable with its ubiquitous blossoming flowers and autumn unfolds fantastic Longsheng Rice Terraces. However, you'd better think twice before visiting the country in the first week of May or October, during busy Labor Day and National Day Weeks. This is the case during the Mid-Autumn Festival as well.
Summer in the Heavenly Empire is hot and humid, but it's also the perfect time for exploring Tibet or climbing Kongur Tagh.
Winter is another low season in China, as it brings biting cold and snow to virtually every part of the country. However, it's a great time in the city of Harbin with its International Ice and Snow Sculpture Festival. Also, remember the Chinese New Year travel madness. Try your best to travel around it!