I lived in Tulsa 1968 to 1970. Once billed as “America’s most beautiful city” I’m easily convinced it is easily one of America’s hottest. It seems to sit in a bowl of sorts between the Osage Hills and Ozark Uplift soaking up sun and humidity.
All of the South swelters in a sauna for the summer. Not at all a dry heat but the SW part in Texas and Oklahoma get no rain at all many summers. A lot of days I look longingly East to central Arkansas and cloud tops with mostly parched skies to our West. 30 miles and only just 600 to 800 feet higher a lot of days are 3 to 5 degrees cooler but certainly not cool.
So it goes.
You can definitely tell the difference between temps in Ft Smith and the river area and NW Arkansas. Often 5-10 degrees different as the NW is cooler, but not much.