Temperatures here have gone up nearly 20 degrees in just a few days. So it is hard for anyone to adjust.
But it is especially dangerous for very young children, the elderly, the obese, and people taking certain medications, such as antihistamines, antipsychotic drugs, some blood pressure and Parkinson's drugs.
These groups of people need to take extra precautions, some are heeding that call.
The lunchtime crowd was a little bigger than usual at the Montco Senior Adult Activity Center today.
It was a cool sanctuary for those seeking relief from the heat.
89-year-old Louise Christmas decided not to tough it out at her non-air-conditioned home.
"I have a little house in east norriton township, and it's going to be too hot there, so I decided to come in and play bridge with the girls," Louise told us.
In addition to bingo, there were plenty of other activities.
"We have line-dancing here, we run zumba, we have a billiard room, and puzzles. We have a bingo group here, and things like that," said Pat MacKenzie, the activities director for Montco SAAC.
Normally, the center caters to members, but in this sizzling weather, officials say non-members, are welcome, too.
Staffers say they were working hard this morning to encourage one man to come in.
"He has an air conditioner, but he doesn't want to turn it on, because the cost to run it is too expensive. So they try not to run the air conditioners even if they have them. So we strongly encourage you to put your pride aside, there is help, for the bills and things. We want you to be safe, first and foremost," said MacKenzie.
In addition to the heat, the high humidity can raise the risk for heat-related illnesses, even for healthy people.
Warning signs for heat exhaustion include: fatigue, nausea, dizziness, and headaches.
That can progress to life-threatening heat stroke.
Symptoms include: hot, dry skin, confusion or a loss of consciousness.
