PHILADELPHIA, July 2 (Reuters) - World Cup fans are being confronted with punishing ⁠temperatures in Philadelphia this week, as a heat dome threatened to add ‌extra sizzle to Saturday's last-16 showdown between Paraguay and France on the American Fourth of July holiday weekend.

A heat dome has settled over the eastern half of the United States and Toronto, ​bringing searing heat and sweltering humidity to World Cup ⁠host cities including Philadelphia, where ⁠Kylian Mbappe's side hope to continue their relentless march through the tournament.

"We're not used ⁠to ‌this heat back at home," said Kerim Alan, a World Cup fan from Manchester, England. "So, you know, we'll put up with it for ⁠a couple of hours, and then we'll get to the ​AC."

The spiritual heart ‌of the American revolution is expected to see a major influx of ⁠fans for the ​game and tourists for the United States' 250th anniversary celebrations, with extreme heat testing the party spirit.

Temperatures are expected to get close to 100 degrees Fahrenheit (37.8°C) on Saturday, according ⁠to AccuWeather, with conditions posing potential risks.

"Spectators will ​spend hours in direct sun with little shade, and that sustained exposure is where heat illness takes hold. Fans from cooler climates are especially vulnerable, since their bodies ⁠haven't adapted to the heat and humidity that we’ll see in Philadelphia this week," AccuWeather meteorologist Tyler Roys said in a statement.

"At these temperatures, staying hydrated, seeking shade frequently, and wearing light clothing aren't just comfort tips, they're safety essentials."

Cooling ​areas at the local fan fest offered some relief.

"I'm ⁠used to this weather, but I think the main factor here is the humidity, ​because we're close to the river and humidity ‌just makes it much warmer than it should ​be," said Alan Assainov, a Temple University student from Kazakhstan.

(Reporting by Kevin Fogarty and Thando Hlophe, writing by Amy TenneryEditing by Toby Davis)