A "temperature readout" refers to the measurement or display of the current temperature. It lets you know the exact temperature at a given time. Full definition
The climate controls feel especially premium, with temperature readouts built into the knobs. (cnet.com)
Farther down the center stack, the 2017 Hyundai Elantra spied here has dual - zone automatic climate control, with a digital temperature readout flanked by rotary temperature controls and an assortment of other buttons. (automobilemag.com)
The top level, in line with the driver's view above the steering wheel, features a digital speedometer, fuel gauge and engine temperature readout. (hybridcars.com)