Mexico has registered 48 deaths in a series of heat waves since March, the government said Friday, May 24, as scientists warned that new temperature records could be coming.
More than 950 people have suffered various health effects over the same period, according to the health ministry.
Last year, Mexico reported a record 419 heat-related deaths in the hot season, which runs from March to October, in a country of 129 million people.
President Andres Manuel Lopez Obrador described this year's heat as "exceptional." "It's a very regrettable natural phenomenon related to climate change," he said at his regular morning news conference.
High temperatures and a lack of wind were exacerbating the pollution problem in Mexico City in particular, Lopez Obrador added.
The capital, which sits at 2,240 meters (7,350 feet) above sea level, has traditionally enjoyed a temperate climate and few homes have air conditioning.
But thermometers in Mexico City reached a record 34.3°C (93.7°F) on May 9, the National Water Commission said.
The northeastern state of San Luis Potosi registered a high of 49.6°C (121.3°F).
Scientists from the National Autonomous University of Mexico warned that more records could be broken in the next two weeks.
This year is on course to be "the warmest year in history," Francisco Estrada, coordinator of the university's Climate Change Research Program, said at a press conference.
It is not just humans that are suffering – in southern Mexico dozens of howler monkeys have dropped dead, apparently due to the heat.