I don't think that the outside temperature reading is always correct
On several occasions, i have driven to a location in the early hours of the morning & had to wait several hours on a semi truck to cross into the USA from Mexico
The early morning temperature may be 56° F when i shut off the engine, i leave the key turned to the ACC position & listen to the radio while waiting.
When the semi comes across the Border, i will will have taken off my coat because of the temperature change, I Start up my Ram & the temperature gauge will still read 56° F & will continue to read that until i have driven to the main highway, about 10 miles & then it will begin to correct the temp reading.
I find it very strange that i can be on the verge of sweating & the gauge shows that it is still chilly