I’m using area cards and room temperature is correctly shown on the card, very nice feature btw. It works if it is somehow a discrete sensor received / provided by MQTT sensor. However I’m using also in two rooms aqara window sensors, received by ZigBee bridge. These window sensors also provide a temperature. However this temperature is not shown on area card, even is assigned to same area room…
I have the same problem with the Area Widget - regarding to the tempreture coming from my homematic thermostate.
This is sadly missing and i don’t know how to enable the temparture for the Area:
To get temperature on area card (or any other type of sensor), you must have a sensor with device_class: temperature in the area, and it must not be a diagnostic sensor.
If you only have a diagnostic sensor or a climate entity, you can use a template to create a temperature sensor for the area, and that will be shown on area card.