My thermostat is right next to my garage door, which is not insulated. This is probably where the majority of heat enters the house. So the thermostat thinks it is warmer than it is.

I’ve got an Ecobee thermostat and they sell little temperature sensors that you can place anywhere in your house. You can configure which sensors are used at which time - for example I have a sensor in my bedroom, and configured it to only look at the bedroom temperature overnight. If you select multiple sensors, it averages them.

It’s a decent solution to this problem.