Shanghai's 'unusual' Warm Climate Explained

Author: Benelux Chamber Shanghai

As many of our members know and experience every year, summer has once more arrived at Shanghai’s doorstep! Shanghai, the bustling metropolis in eastern China, is known for its vibrant culture, modern skyline, and dynamic economy. However, it is also characterized by a climate that can be challenging, particularly during the summer months when heat and humidity reach their peak.




Shanghai's climate is classified as humid subtropical, influenced heavily by the East Asian monsoon. The city experiences four distinct seasons, with hot, humid summers and cold, damp winters. The summer months, from June to September, are particularly noteworthy for their intense heat and high humidity levels.

During summer, temperatures in Shanghai often soar above 30°C (86°F), with July and August being the hottest months. It is not uncommon for temperatures to reach or exceed 35°C (95°F) during heatwaves. The high temperatures are accompanied by significant humidity, with average relative humidity levels often exceeding 80%.

The high humidity in Shanghai is primarily due to its geographical location near the Yangtze River Delta and the East China Sea. Moist air masses from these bodies of water contribute to the high humidity levels, especially when combined with the city's dense urban environment. The abundance of concrete and asphalt in Shanghai exacerbates the heat through the urban heat island effect, where human activities and infrastructure absorb and re-radiate heat, making the city warmer than surrounding rural areas.

Moreover, the monsoon season, which typically occurs from June to September, brings frequent and heavy rainfall. This period, known as the "plum rain" season, results from warm, moist air from the south clashing with cooler, drier air from the north, leading to prolonged periods of rain and further increasing humidity levels.

We’ll finish this articles with some numbers:

  • Hottest Months: July and August (29 degrees C)

  • Coldest Month: January (5 degrees C)

  • Wettest Month: August (21 CM)

  • Windiest Month: April (14 km/h)