BEIJING -- Although many Chinese believe the "Four Furnaces" of Chongqing, Nanchang, Wuhan and Nanjing are the country's hottest cities, meteorological authorities have debunked the popular belief after comparing temperatures in cities nationwide.

Zhang Cunjie, a researcher at the National Meteorological Center, said an analysis of the last 31 years of meteorological data from China's provincial capitals and municipalities has revealed that the country's hottest cities are actually Chongqing, Nanchang, Hangzhou and Fuzhou, with the latter two taking the place of Wuhan and Nanjing.

The NMC analyzed the number of hot days and consecutive hot days in different cities, as well as the average high and low temperatures during the summer season. A heat index that combines air temperatures and relative humidity to determine the temperature perceived by humans was also used.

Zhang attributed the lower temperatures in Wuhan and Nanjing to climate evolution in past decades.

"In the 1990s, regions along the Yangtze River witnessed more rainfall and floods than before, so air temperatures were relatively low and hot days were relatively few," Zhang said.

Data from the NMC showed that China's average temperature increased by 1.38 degrees from 1951 to 2010, an average of 0.23 degrees every 10 years, roughly in line with the pace of global warming.

In the past three decades, Chinese cities have seen hotter summer days and more extreme temperatures than ever before, Zhang said.