Direct sunlight can cause a thermostat’s temperature sensors to heat up, so it may think that the ambient temperature in the room is higher than it actually is. When this happens, your thermostat may not keep your home the temperature that you want, making things uncomfortable for you. Google Nest thermostats use Sunblock to compensate for direct sunlight and keep your home comfortable.
When Sunblock is active, a sun icon appears on your Nest thermostat's display and on the Nest app’s thermostat screen.