Record heat waves have been baking East Asian countries including Korea, Japan, China and Taiwan due to a Pacific high pressure system.
In South Korea, the scorching weather has killed at least six people and left hundreds sickened over the past week, Seoul officials said.
Heat wave alerts have been issued in most parts of the country, with peak temperatures hovering around 35 degrees Celsius.
Tropical nights have also continued as night temperatures stayed above 25 degrees.
On Sunday, two elderly women in the Jeolla provinces were found dead after working at a farm in the daytime and a 57-year-old man in Ulsan died in his sleep.
As of Saturday, 663 people were reported to be suffering from heat-related illnesses, according to the Central Disaster and Safety Countermeasures Headquarters.
In Japan the temperature topped 40 degrees Celsius in two cities on Sunday, leaving at least four people dead over the weekend, officials and reports said.
The Japan Meteorological Agency said the temperature reached 40.6 C in Kofu, 100 kilometers west of Tokyo, in the mid-afternoon.
The weather agency had warned early Sunday that the temperature would soar past 35 C in 39 of the country’s 47 prefectures. It warned people to drink plenty of water and use air conditioners.
On Saturday the mercury topped 40 C for the first time in Japan since August 2007, when it had reached an all-time high of 40.9 C in two separate cities.
An 84-year-old woman and a 66-year-old man in western Japan died from heat stroke on Saturday, Kyodo news agency said.
Two more deaths from heat stroke were confirmed by officials on Sunday.
An 80-year-old woman died in the hospital after she was found collapsed at her wooden home Sunday morning in Arita, a city south of Osaka, a medical evacuation official said. The living room where she was found was not air-conditioned.
In Saitama north, of Tokyo, a 60-year-old man died in the hospital after he was found unconscious on a street on Saturday afternoon.
China has been in the grip of a heat wave for the last few weeks, with some areas recording their hottest summer for 140 years.
In July a heat wave in the country claimed at least a dozen lives, according to media reports.
Meanwhile, a powerful typhoon made landfall in the northern Philippines on Monday, toppling power lines and dumping heavy rains across mountains, cities and food-growing plains, leaving at least 23 fishermen missing.
Typhoon Utor, described as the strongest typhoon globally so far this year, slammed ashore in the mountainous eastern Aurora province with sustained winds of 175 kilometers per hour and gusts of up to 210 kph.
About 1,000 residents in the central Bicol region spent the night in shelters while Aurora province was without power, the national disaster agency said. Radio stations reported that roofs were blown off and a covered basketball court washed away in the town of Dinalungan.
By Lee Hyun-jeong and news reports