CTtemperaturesmay feel like it's over 100 degrees the next few days. Here's what you need to know.

Jul. 27—Worldwide, temperatures have been so hot this July that scientists believe it may already be the warmest human civilization has ever seen, the Associated Press reported. The World Meteorological Organization and the European Union's Copernicus Climate Change Service on Thursday said the Earth's temperatures have drifted over 1.5 degrees Celsius, hotter than pre-industrial times, 16 days this month.

The measurement is a key data point for climate change; countries agreed in the 2015 Paris climate accord to pursue holding global warming below the 1.5 degrees Celsius threshold. Scientists and governments have warned that crossing the line could bring about some of the worst consequences of climate change, including severe and frequent droughts, heat waves and rainfall.

The National Weather Service described the weather as the "hottest air mass of the season," and said heat index values — a measurement of how the air feels when the heat is combined with humidity — will likely reach 112 in the tri-state region on Friday and possibly again on Saturday. Heat advisories issued for Connecticut show index values up to 104 are forecast in parts of northern Connecticut.

Officials have warned the string of hot days could lead to cases of heat-related illness.

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"A heat wave is just a very prolonged period of unusually hot weather, and it's unfortunately one of the most common causes of environmental death in the United States," said Dr. Natalie Moore, an emergency physician at UConn Medical Center in Farmington.

"Folks do tend to get sick within about two days of excessive heat, which is why the prolonged period is the key to this," she said. The prolonged heat can cause a variety of heat-related illnesses, including heat exhaustion and heatstroke, Moore said.

"Tt's going to occur when your body is really unable to cool itself off by sweating," she said.

Some signs and symptoms she said people should watch out for include very hot and dry skin; excessive sweating; a fast pulse; feeling lightheaded, dizzy or nauseous; muscle cramps; headaches and fever.

"If you're having a fever greater than 104 degrees Fahrenheit, that would certainly be a time that you should seek care," Moore said.

Moore said people who are feverish should try to take their temp using the type of thermometer that goes under your tongue. "The forehead ones aren't going to work as well, especially if you just walked through the door and you were outside for a prolonged period of time," she said.

Eversource, the state's largest electrical utility, said customers in Connecticut use about 35 percent more electricity during the summer months. The company said its crews are ready to respond to any issues that arise during periods of extreme heat.

"We all use more energy during the summer months as we try to keep cool, running our air conditioners, fans and other appliances, and that demand usually peaks when we see prolonged hot weather for multiple days," Steve Sullivan, Eversource's president of Connecticut electric operations, said in a statement Wednesday.

He said the company prepares for the extra usage "months in advance" by inspecting electrical systems overhead and underground " so we can detect and address any issues well beforehand."

The company said residents can help manage the energy they use by keeping air conditioners as warm as they comfortably can and ensure air flow and vents are clear of obstructions. Major appliances like washers and dryers can also be run early in the morning or late in the evening when demand for electricity is low, he said.

Other tips include using blinds to block sunlight and keep inside temperatures low, switching to energy-efficient LED lighting, which run cooler and last longer, and setting ceiling fans to rotate counter-clockwise in the summer.

The state's extreme hot weather protocol has also been activated. The protocol allows state and local officials to coordinate the opening of cooling centers that are intended to serve vulnerable people. A list of local cooling centers is available through the United Way.

The American Red Cross noted that some 80 million people were living with dangerous temperatures as the summer's heat waves moved across the U.S.

"The National Weather Service reports above-normal temperatures will heat nearly everywhere in the continental U.S. for as long as the next two weeks," the Red Cross said. "Here in Connecticut, an extreme hot weather protocol is in effect until Sunday morning."

"We've been seeing some cases of dehydration, fatigue, lack of energy and we correlate that with the humidity that we've had the past few weeks," said Dr. Syed Hussain, medical director of Hartford Healthcare's urgent care centers in the Fairfield region. Those affected have included patients who are older adults or have underlying conditions like asthma, diabetes, chronic lung disease and co-morbidities, he said.

The heat and humidity arrive after the state saw poor air quality from smoke drifting from wildfires burning in Canada, he noted.

"When you have the humidity that high, it makes the air very heavy and people who have underlying lung conditions, heart conditions and other issues that I had mentioned — they tend to suffer more," Hussain said.

He said they've been asking patients to remain in air-conditioned places and encouraged people to check on their neighbors. Children also tend to run around more than adults and will become dehydrated quickly. He said it's important for adults to bring children inside especially during the peak hours in the afternoon.