North Texas swelters in heat. How many 100-degree days? When will it cool down?

A relentless heat wave has gripped North Texas, delivering the hottest temperatures of the year this week.

As people scramble indoors for air conditioning, electricity bills have soared, and most people report the heat is affecting their outdoor activities. As the National Weather Service issues multiple excessive heat warnings, here are five things to know about the heat.

1. Just how hot is it?

Thursday hit 101 degrees at Dallas-Fort Worth International Airport, a bit cooler than Monday, which at 107 degrees was the hottest day of the year. Humidity has remained relatively low, so the heat index, a measure of how hot it feels, felt roughly the same as the temperatures.

“We’re in a hot and dry pattern, which is very typical for North Texas in August,” said Sarah Barnes, a meteorologist with the weather service in Fort Worth.

2. How many 100-degree days has Dallas-Fort Worth seen?

So far, North Texas has recorded 22 days of at least 100 degrees. A typical North Texas summer has has roughly 20 days of at least 100 degrees, Barnes said.

Overall, this summer has been more mild than last year, when the region recorded 55 days of 100 degrees or more and Texans were baking bread in mailboxes and cookies in cars. And it does not come close to the record, when 2011 saw a whopping 71 days of at least 100 degrees.

3. When will it cool down?

A tiny bit of relief is on the way. Friday and Saturday will be hot, with highs around 101. But beginning Sunday, temperatures will drop into the upper 90s for several days.

We will likely have to wait a little longer for substantial relief. On average, North Texas gets its first solid cold front of the season in the second half of September, with lows typically dipping to 60 degrees by Sept. 17, according to the weather service. The first day of fall is Sept. 22, and the average first freeze typically comes Nov. 22.

4. What is the highest temperature ever recorded in Dallas-Fort Worth?

The highest temperature ever recorded in Dallas-Fort Worth came in 1980, according to the weather service. On June 26 and 27 that year, the temperature reached 113 degrees. And last year, it hit 110 degrees in September.

5. How are people faring?

For some of us, the heat is a nuisance. But for others, particularly older adults, those who work outside and people without reliable air conditioning, it can be dangerous.

On Aug. 15, Dallas County reported the first confirmed heat-related death — a 79-year-old Dallas woman who lived in the 75227 ZIP code — of the season. Last year, heat-related illness caused more than 350 deaths in Texas, a state record.

So far this year, Dallas County authorities have treated 958 residents for heat-related illnesses, including heat exhaustion, stroke or cramps, according to the county’s dashboard. To stay safe in the heat, health authorities recommend limiting time outdoors if possible and staying hydrated.

“We want to keep reminding people to take those safety precautions,” Langfeld said. “Take breaks in the shade if you have to be outside, and stay hydrated.”