The best times to visit Shanghai are in spring or autumn. The city has a subtropical maritime monsoon climate, with four distinct seasons. Generally, the warm spring and cool autumn are the more comfortable seasons. While summer and winter are far less pleasant. Overall, Shanghai enjoys a mild and moist climate.
Shanghai’s temperature is the highest in July and August. For ten days or so in these two months, the temperature can reach 35 degrees centigrade. The coldest period is from the end of January to early February – usually during the Chinese Spring Festival. This awfully cold period will last for about three days but it seldom snows, in fact there has been none for years. From March to May, the conditions are pleasant so this is the best season for traveling.
One thing to mention is what is called the Mei-Yu Season which in English is the ‘Plum Rain Season’. This lasts for about a month commencing in early summer when the plums ripen along the middle and lower reaches of the Yangtze River. During this period from mid-June to early July it is difficult to tell whether it will be wet or dry and the rainfall will often equal twenty-five per cent of the city’s annual total! From late August and through the first twenty days of September, typhoons can bring heavy rain in their wake. These periods are best avoided by the traveler but should you decide to visit be sure to bring an umbrella. Of course, the umbrella can also be used as a protection from the strong ultraviolet radiation on the sunny days. Generally you will need a light coat and sweater in spring and long and short sleeved shirts in summer. In autumn, long-sleeved shirts, sweater and coat are necessary, while sweater and overcoat are appropriate in winter.