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.
I’m using the same sensors in all my rooms. Some of my rooms show their temperature on the card. Others don’t. I’m using a D&W sensor that was temperature as a diagnostic entity like OP. All dashboard configs are the same. It’s just… Strange.