In terms of climate, the best time to visit Guangzhou is between October and February Alternatively (autumn and winter), April and May are also good months.
Since summer season is the peak tourist season, travelers should avoid visiting Guangzhou during this time. If you choose to visit Guangzhou during summer, make sure that you have made your reservations well in advance. Avoid visiting Guangzhou during Chinese New Year ((late February-early March). Most of the Chinese places close down during this time. The Chinese people travel during this time and getting reservations become difficult. Late spring is the best time to visit Guangzhou.
Guangzhou has a sub-tropical climate with humidity levels at their highest in the summer, so unless you enjoy Turkish steam baths, this is a season to avoid! Typhoon season is from June to October. Please note that the Canton Trade Fairs take place annually during the 3rd and 4th weeks of April and October, so finding accommodation at those times can be difficult (See the warning section under Sleep).