We have upstairs and downstairs thermostats at the house.
I generally keep the downstairs AC at 74F/23C and the upstairs AC at 76F/24C in the summer, and the downstairs heater at 66F/19C and the upstairs heater at 70F/20C in the winter.
It is funny how those indoor summer temperatures would be perceived as sweltering in the winter, and those winter temperatures perceived as frigid in the summer.
Outdoor temperatures can deviate from the above by at least 5F/3C and still be entirely comfortable, and actually I am quite happy down to about 50F/10C outside in the winter.