Shanghai Weather Becoming More Extreme

Shanghai weather, especially the humidity, can take some time for expats to get used to.

Shanghai enjoys a subtropical climate with long rainy seasons, hot summers and usually mild winters. 

The summer of 2017 is forecasted to be hotter and longer than last year, with temperatures exceeding 40 degrees Celsius, 104 degrees Fahrenheit. Already some of the heat records set in the summer of 2013 have begun to tumble, including the hottest day on record of 40.8 degrees Celsius.

We take a look back at that record breaking summer of 2013 below. But first lets look at this summer and the four seasons in Shanghai.

Summer Shanghai Weather

The official start of summer in Shanghai is denoted as the start of 5 consecutive days with the average daily temperature exceeding 22 degrees Celsius, 71.6 degrees Fahrenheit. This usually happens in late May and occurred on May 18th this year.

On July 14th, 2017 the temperature hit 39 degrees extending the cities first Orange alert to a third consecutive day.

The orange alert is the second highest in the 3-tier Shanghai weather extreme-temperature alert system, lifted when temperatures are expected to hit 37 degrees. It follows the Yellow alert lifted when temperatures are expected to hit 35 degrees.

The city's highest Red alert is issued when the temperature is expected to hit 40 degrees.

July 12th, 2017 marked the start of the ‘sanfu’ season in the Chinese lunar calendar, which signifies the hottest days of summer and lasts about 40 days. 

Along with extreme heat the weather in Shanghai during the summer is marked by occasional thunderstorms, gales, hailstorms, lightning and typhoons. 

Shanghai Summer Weather Records Begin to Topple

On July 21st, Shanghai broke its all time high temperature record, hitting 40.9 degrees Celsius, 105.62 degrees Fahrenheit.

This is the highest temperature ever recorded in Shanghai at its benchmark weather station in downtown Xujiahui district since records started to be taken in 1873.

Plum Rain Season in Shanghai

Shanghai's Plum Rain season, known as MeiYu JiJie 梅雨季节 in Chinese, occurs during the summer months. 

This is when Shanghai weather is characterized by high temperatures and extreme mugginess with intensive and continuous downpours.

This year's plum rain season lasted from June 19th to July 5th, six days shorter than the average 23 days and 14 days less than the record of 31 days set in 2016.

Shanghai Air Pollution in Summer

Although fine particulate matter air pollution in Shanghai, aka PM2.5, is usually much lower in the summer months than the winter, Ozone air pollution in Shanghai can be a serious issue during this time of year. 

Shanghai Summer Health Issues 

Dermatitis, eczema, allergic conjunctivitis and respiratory infection cases all increase in Shanghai during the summer months, especially for children and the elderly.

Rabies is also a concern during the summer in Shanghai as dogs are much more prone to biting during extreme heat. It is critical to visit a doctor to get vaccinated immediately if you are bitten, even slightly. At least one person in Shanghai died from rabies in the summer of 2017 because he did not get vaccinated in time.

Shanghai Summer Air Pollution

Spring Shanghai Weather

The meteorological start of Spring in Shanghai is the start of five consecutive days with average temperatures above 10 degrees Celsius, 50 degrees Fahrenheit.

This usually occurs in mid-March. In 2017 March 25th was the official start date of Spring.

In 2016 it occurred on February 9th, the earliest date ever since this record started to be kept in 1873.

Shanghai Winter Weather

The meteorological start of Winter Shanghai weather is the start of five straight days with average daily temperatures under 10 degrees Celsius, 50 degrees Fahrenheit. This occurred on November 23rd in 2016.

During the winter of 2016-2017, Shanghai experienced the warmest December and January since temperatures were first recorded. 

The average temperature was 10 degrees Celsius in December 2016. The yearly average for this time of year is 7.3 degrees. 

In January, the average temperature was 7.5 degrees.

This, after the winter of 2015-2016 saw the coldest temperatures in 35 years, hitting minus 7.2 degrees Celsius, 19.04 degrees Fahrenheit.

Shanghai does get a little snow most winters, but it usually melts before it can stick to the ground. Only during the winter of 2008 did Shanghai experience a large scale blizzard which closed highways and train lines in and out of the city for several days.

Shanghai Autumn Weather

The meteorological start of Autumn in Shanghai is the start of five straight days with average daily temperatures under 22 degrees Celsius, 71.6 degrees Fahrenheit. 

This occurred on October 8th in 2016. 

The average length of Autumn in Shanghai is 61 days, but was only 46 days in 2016. The Autumn of 2016 also experienced the wettest weather in Shanghai since 1875.

Weather in Shanghai in the Summer of 2013

Many cities in China including Shanghai recorded all-time record high temperatures in the summer of 2013.

On July 26th, 2013 Shanghai hit 40.6 degrees Celsius, breaking its previous all-time record high temperature of 40.2 degrees set in 1934 at its Xujiahui weather reporting station, where it has been measuring temperatures since 1873.

Later, on August 8th the record was broken again, hitting 40.8 degrees.

During the summer of 2013 Shanghai issued several red heat alert warnings. From August 6th to August 9th, Shanghai experienced four consecutive days of 40 degree plus weather for the first time in its history.

During the month of July Shanghai had 25 extreme temperature days, when the mercury climbs above 35 degrees, breaking the old record of 23 days set in 1934.

Many Shanghai residents complained that the temperature was probably higher than that officially reported, and proved their point by showing thermometers placed on the ground with much higher temperature readings.

They complained that the government was reporting lower temperatures in order to avoid the need to take certain costly measures, such as allowing municipal workers to stop work outdoors.

A senior forecaster at the National Meteorological Center, however, explained that this was due to the methodology for temperature measurement. China follows international standards and measures the temperature 1.5 meters off the ground.

Meteorologists at Shanghai Meteorological Bureau stated the large number of extremely hot days in July 2013 was due to the subtropical anticyclone in the western Pacific.

One of the few records which was not broken during the summer of 2013 was the total number of extreme temperature days above 35 degrees for the whole summer, which remains the 55 such days achieved in 1934.

At least 11 people were reported to have died due to the extreme weather in Shanghai in July 2013. Thousands of fish also became victims, as the water temperature in fish farms and local rivers reduced the amount of oxygen in the water.

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