Example of creating a temperature sensor in Home Assistant from an average of other sensors.

sensor_temperature_calc.yaml

platform: template
sensors:
  sensor_temperature_calc:
    value_template: >-
      {% set temps = [
          states('sensor.01_temperature')|float(0), 
          states('sensor.02_temperature')|float(0),
          states('sensor.03_temperature')|float(0)
        ]|reject("==", 0.0) | list %}
      {{ ( temps | sum / temps | count ) |round(0) }}
    friendly_name: Sensor Temperature
    unit_of_measurement: "F"