Scientists say global warming is exacerbating adverse weather, with many countries experiencing deadly heatwaves and temperatures hitting records across Southeast and South Asia in recent weeks.
"At 13:09, the temperature at Xujiahui station hit 36.1 degrees Celsius (97 degrees Fahrenheit), breaking a 100-year-old record for the highest temperature in May," a post on the service's official Weibo account read, referring to a metro station in the centre of China's largest city.
The temperature at the bustling station climbed even higher to 36.7C (98F) later in the afternoon, the meteorological service said.
That put it a full degree above the old record, 35.7C, which has been recorded four times previously, in 1876, 1903, 1915 and 2018, according to the service.
Shanghai residents sweltered under the early-afternoon sun, with some apps showing a "feels like" temperature estimate of more than 40C (104F).
"I almost got heatstroke, it's really hot enough to explode," read one post on Weibo.
A man who gave his surname as Wu told AFP: "It's an environmental problem, the world is going to get hotter and hotter."
"I have the feeling that summers are becoming much hotter every year. I'm turning on the air conditioning sooner than before."
Parts of India saw temperatures above 44C (111F) in mid-April, with at least 11 deaths near Mumbai attributed to heat stroke on a single day.
In Bangladesh, Dhaka suffered its hottest day in almost 60 years.
The city of Tak in Thailand recorded its highest-ever temperature of 45.4C (114F), while Sainyabuli province in Laos hit 42.9C (109F), an all-time national temperature record, the study by the World Weather Attribution group said.
A recent report from the United Nation's Intergovernmental Panel on Climate Change warned that "every increment of global warming will intensify multiple and concurrent hazards".
In May, the United Nations warned it is near-certain that 2023-2027 will be the warmest five-year period ever recorded, as greenhouse gasses and El Nino combine to send temperatures soaring.
There is a two-thirds chance that at least one of the next five years will see global temperatures exceed the more ambitious target set out in the Paris accords on limiting climate change, the UN's World Meteorological Organization (WMO) said.
The 2015 Paris Agreement saw countries agree to cap global warming at "well below" two degrees Celsius above average levels measured between 1850 and 1900 -- and 1.5C if possible.
The global mean temperature in 2022 was 1.15C above the 1850-1900 average.
"Although it makes me worried, on the policy level we have to look to the country," Shanghai resident Jenny told AFP on Monday.
"Only the authorities will have the capability to be able to make changes. Because what we can do as individuals is very limited."