Nanjing has a humid subtropical climate with plenty of rainfall. The four seasons are distinct in Nanjing, with hot summers and cold winters. The spring is warm and humid, and the rainy season falls on June and July. In summer, Nanjing becomes one of the three "furnace cities" along the Yangtze River, together with Wuhan and Chongqing. Autumn is a short but the most pleasant season. Though considered a southern city in China, Nanjing is cold in winter with occasional snow.
The average annual temperature is 16 °C (61 °F). The hottest month is July, with an average high of 32 °C (90 °F) and an average low of 25 °C (77 °F). The coldest month is January, with an average high of 7 °C (45 °F) and an average low of -1 °C (30 °F). The weather is overall humid in Nanjing, with about 117 rainy days yearly, and an annual average precipitation of 1106 millimeters (43.5 inches). The best time to visit Nanjing is during autumn, when the weather is cool and dry. Osmanthus flowers are in full blossom in autumn, leaving sweet scents flowing all over.
Spring
Spring is from March to May. The weather warms up, and it is humid, with changing temperatures. It may warm up for a few days and turn cold later. Wearing sweaters and coats are enough to cope with the weather, but also prepare long-sleeve shirts for the day when it gets warmer.
Summer
Summer is from June to September, with extremely hot and humid weather. It is one of the "three furnaces" along the Yangtze River Delta, with Wuhan and Chongqing. Rainfalls concentrate in June and July. The temperature easily reaches above 34 °C (93 °F). The highest temperature is in July, hitting above 40 °C (104 °F). Prepare summer clothes, umbrella and sun protection.
Autumn
Autumn is from October to November. It is the best time of the year for traveling in Nanjing, with pleasant cool and dry weather. There are sharp and frequent intervals of temperature changes. Shirt, thin sweater and coat are enough to cope with the weather.
Winter
Winter is from December to February. It is cold with heavy humidity in Nanjing, with occasional snow. January is the coldest month with the low temperature dropping to -7 °C (19 °F). The average low and high temperature is respectively at 0 °C (32 °F) and 9 °C (49 °F) in December, -2 °C (29 °F) and 7 °C (44 °F) in January, and 0 °C (32 °F) and 8 °C (47 °F) in February. Down jackets or cotton-padded coat, sweater and thick jeans are suitable to cope with the weather. Read where to travel in winter?