The report said that by the 2050s, over 1.6 billion people living in over 970 cities will be regularly exposed to three-month average temperatures reaching at least 35 degrees Celsius.
The Northern California blaze Friday forced as many as 7,500 residents to leave. Suzi Brady, a Cal Fire spokeswoman, said several people were injured and taken to a hospital.
The wheat crop decline is likely to have been caused by a heatwave that resulted in shrivelled grains in the northern states of Punjab and Haryana.
The world's second-largest economy has experienced over 70 days of heatwaves, flash floods and droughts, phenomena that scientists say are becoming more frequent due to climate change.
The mercury has soared beyond 40 degrees Celsius in Sichuan province this week, fueling massive demand for air conditioning and drying up reservoirs in a region reliant on dams for its electricity.
The wheat production is estimated to have declined due to heatwave that resulted in shrivelled grains in the northern states of Punjab and Haryana.
Spain water crisis: Historic drought, heatwave grills country; reservoirs at just 25 per cent of their capacity
Spain is the second most visited country and significant amounts of water are used in tourism infrastructures. But agriculture absorbs the bulk -- over 80 per cent -- of the country's water resources.
Saturday marked the "Great Heat" day on China's traditional calendar, long recognised as the hottest period of the year, but this summer has been exceptionally warm.
Even if all the countries decrease emissions to stick to the 2 degree-level as per the Paris Agreement, there will still be an increase in extreme weather and climate events.
And, as Europe counts the cost of another record-shattering heatwave, the analysis showed how even nations with typically few climate-linked crises will need to adapt as global temperatures rise.
Waterlogging in some key stretches chokes traffic in city
The Carlos III Health Institute (ISCIII) said that 169 deaths occurred on July 17 alone, according to the news agency, Xinhua.
At least two people were hospitalised in the Greek capital with breathing problems and minor burns.
It did feel like for days the prospect of hitting that 40-degree mark was somewhat of a preoccupation, the previous record being 38.7 degrees Celsius three years ago.
The WMO held a joint press conference with the World Health Organization, its sister UN agency, about the fierce heatwave hitting western Europe.
The Met Office red warning of danger to life from extreme heat remains in place for much of central, northern, and south-east England, including the capital city.
The heatwave is the second to engulf parts of southwest Europe in weeks, and blazes burning in France, Greece, Portugal and Spain have destroyed thousands of hectares of land.
IMD further predicted that rainfall with thunderstorms and lightning are very likely to occur over Punjab, Haryana, Chandigarh-Delhi and Uttar Pradesh during the next three days.
The unprecedented warning implies there is a danger to life across all age groups and is classed as a national emergency.
In southern France since Tuesday afternoon, a wildfire ripped through 800 hectares of pine trees just south of Bordeaux, pushing 150 residents to evacuate their homes.