North America in the grip of a dangerous heatwave

Extremely hot weather has started to hit most of the United States, with temperatures set to peak over the weekend, meteorologists say.

The heatwave could affect about 200 million people in major cities like New York, Washington and Boston in the East Coast, and the Midwest region too.

In some places, temperatures could be close to or exceed 38C. Parts of Canada are also being hit.

The governor of the state of Wisconsin declared a state of emergency after two fires broke out at electric substations in Madison. In New York, Central Park festival OZY Fest has been canceled due to the heat wave, New York City officials said Friday.

Experts link more frequent heatwaves in recent years to climate change.

The world experienced its hottest June on record this year, with an average temperature worldwide of 61.6F (16.4C), according to new data.

To keep Chicago cool, the city has installed hundreds of green alleys, made with materials that absorb less heat than black asphalt. New York City also has a program that paints roofs white to reflect the sun.

Via BBC/CBS/USA Today