Ferocious heat dome is set to shatter hundreds of weather records with sweltering heat and humidity that will last for a week

A record-breaking heat wave is smothering the US, with sweltering temperatures and thick humidity set to last for a week.

More than 270 million Americans will be hit by temperatures of at least 90 degrees this week, and extreme heat warnings are in effect for parts of the country.

The spike is due to a heat dome that has settled over the east and traps hot air as the sun shines continuously, making each day hotter than the last.

Hundreds of records are set to be broken this week as parts of the Midwest and Northeast experience the longest heat wave in decades.

Heat-related illnesses are a serious problem in hard-hit areas, where the electricity grid is under strain and the elderly, children and outdoor workers have been warned to be particularly careful.

A record-breaking heat wave is smothering the US with sweltering temperatures and high humidity, making it feel even hotter than it already is

Forecasters have issued extreme weather warnings for parts of the country from the Great Lakes to the Northeast

Forecasters have issued extreme weather warnings for parts of the country from the Great Lakes to the Northeast

The weather this week will break all temperature records for June, reaching levels normally only seen on the hottest days of July.

Desperate residents have flocked to the beaches and fountains to escape the unusual heat.

Americans in far northern Maine will be hit with sweltering heat well into the 90s this week.

And it will feel even hotter than the thermometer indicates, because the humidity pushes the heat index values ​​into the 100s.

Forecasters have issued extreme weather warnings for parts of the country from the Great Lakes to the Northeast.

Wednesday and Thursday will be the warmest days, but only marginally.

Several major cities will be dangerously hot, including Chicago, Detroit, Cleveland Pittsburgh, New York and Boston.

More than 270 million Americans will be hit by temperatures of at least 90 degrees this week, and extreme heat warnings are in effect for parts of the country

More than 270 million Americans will be hit by temperatures of at least 90 degrees this week, and extreme heat warnings are in effect for parts of the country

The spike is due to a heat dome that has settled over the east and traps hot air as the sun shines continuously, making each day hotter than the last.

The spike is due to a heat dome that has settled over the east and traps hot air as the sun shines continuously, making each day hotter than the last.

The heat wave started on Monday with temperatures rising 15 degrees above normal in the afternoon and remaining high overnight.

They are expected to rise another 25 degrees above normal for the rest of the week.

Some of the hardest-hit areas, like Pittsburgh, haven’t been this warm in more than 30 years.

Pittsburgh’s local weather service said on reached warmer temperatures. -20, 1994).

‘That is the longest stretch of more than 95 degree days ever measured. We have a chance to match or beat that.”

New York, Burlington and Cleveland are all opening cooling centers this week to help residents cope with the heat.

Outdoor workers are given cooling sets.

The heat wave started on Monday with temperatures rising 15 degrees above normal in the afternoon and remaining high overnight

The heat wave started on Monday with temperatures rising 15 degrees above normal in the afternoon and remaining high overnight

Some of the hardest-hit areas, like Pittsburgh, haven't seen this warm in more than 30 years

Some of the hardest-hit areas, like Pittsburgh, haven’t been this warm in more than 30 years

Heat domes work by trapping hot air in place over an area.

The sun then continuously heats the air and without circulation it becomes hotter and hotter every day.

The oven-like conditions don’t get cold enough at night to provide people with relief, increasing the risk of heat-related illness.

The Weather Prediction Service said: “Warm nighttime temperatures that only dip into the mid-70s will provide little to no relief, especially for those without adequate or reliable cooling.”

High humidity will make it feel even warmer than it already is, as people are warned to limit outdoor activities, stay hydrated and check on neighbors.