China sweltered under the hottest June in decades, while rainfall hit records during the month.

The average temperature across the nation hit 21.3 degrees Celsius in June, up 0.9 Celsius from the same period last year and the highest since 1961, the China Meteorological Administration said in a report on Tuesday.

Heat waves blanketed parts of China from June 13 to June 26, affecting over 600 million people. A county in northern Hebei Province saw its temperature hit 44.2 Celsius on June 25.

China has also seen seasonal flooding in several parts of the country, particularly in the hard-hit south that receives the bulk of rainfall as well as typhoons that sweep in from the South China Sea.

The northeastern provinces of Shandong, Jilin and Liaoning saw precipitation rise to the highest levels ever recorded in June, while the national average of 112.1mm was 9.1 percent higher than the same month last year, the administration said.

China is not alone in experiencing higher temperatures and more volatile weather. In Japan, authorities warned of greater than usual stress on the power grid and urged citizens to conserve energy.

Japanese officials announced the earliest end to the annual summer rainy season since the national meteorological agency began keeping records in 1951. The rains usually temper summer heat, often well into July.

On Friday, the cities of Tokamachi and Tsunan set all-time heat records while several others broke monthly marks.

Large parts of the Northern Hemisphere have also seen extreme heat this summer, with regions from the normally chilly Russian Arctic to the traditionally sweltering American South recording unusually high temperatures and humidity. (Xinhua/AP)