I couldn’t find a good way to get some of the aviation weather data I wanted to display on a metar section on my dashboard, so I had to make some templates. The hardest one was figuring out the math for the Density Altitude. Since no one else seems to have a solution posted, I modified mine a bit so it can work for anyone.
Density Altitude Template Sensor
Do you have a sensors section in your configuration.yaml? If not, add this:
# Sensors
sensor:
Most of you can skip that and just add the following code to your configuration.yaml file in the sensors section:
# Density Altitude
- platform: template
sensors:
weather_density_altitude:
friendly_name: "Density Altitude"
unit_of_measurement: "Feet"
value_template: >
{% set QNH = states('sensor.yoursensor_pressure_inhg') | float %}
{% set OAT = states('sensor.yoursensor_temperature_c') | float %}
{% set FA = yourfieldalt | float %}
{% set ISA = 15 - (FA/1000 * 2) | float %}
{% set PA = (FA + 145442.2) * (1 - ((QNH / 29.92126) ** 0.190261)) | float %}
{{ (PA + (120 * (OAT - ISA) ) ) | round(0) }}
You must change three variables in the code above to make this work:
-
Change “yoursensor” above to name of your pressure sensor, in inHg. Example:
{% set QNH = states('sensor.openweathermap_pressure_inhg') | float %} -
Change the “yoursensor” above to name of your temperature sensor, in Celcius. Example:
{% set OAT = states('sensor.openweathermap_temperature_c') | float %} -
Change the “yourfieldalt” above to the elevation of your airfield, in feet.
Denver Example:{% set FA = 5433.8 | round(0) %}
JFK Example:{% set FA = 13 | round(0) %}
Definitions:
PA = Calculated Pressure Altitude
FA = Altitude at Your Airfield
QNH = Current Barometric Pressure (inHg)
OAT = Current Outside Air Temp (C)
ISA = Standard Temp at Your Airfield (C)
Unit of Measure Conversions:
If your sensors aren’t currently using the correct units of measurement, you can also add any of the following to your configuration.yaml file, also under the sensors section:
# Metar Units Conversion
- platform: template
sensors:
# m/s to kts
metar_wind_speed_kts:
friendly_name: "Weather Wind Speed"
unit_of_measurement: "knots"
value_template: "{{ (states('sensor.yoursensor_wind_speed')|float*1.94384)|round(1) }}"
Use the following for other conversions:
# mph to kts:
value_template: "{{ (states('sensor.yoursensor_wind_speed')|float*0.868976)|round(1) }}"`
# m/s to mph:
value_template: "{{ (states('sensor.yoursensor_wind_speed')|float*2.23694)|round(1) }}"`
# mb to inhg:
value_template: "{{ (states('sensor.yoursensor_pressure')|float*0.02953)|round(2) }}"`
# c to f:
value_template: "{{ (states('sensor.yoursensor_temperature_c')|float*(9/5)+32)|round(2) }}"`
# f to c:
value_template: "{{ ((states('sensor.yoursensor_temperature')|float-32)*(5/9))|round(2) }}"`
Again, don’t forget to replace the “yoursensor” to the actual name of your sensor. Example:
value_template: "{{ ((states('sensor.openweathermap_temperature')|float-32)* 5/9)|round(2) }}"
Disclaimer:
NONE OF THIS INFO SHOULD BE UTILIZED IN THE AIRPLANE!
Use this for fun and so you can have a good idea of the conditions before you head to the airport. If you’re a pilot, you already know where to get the info you need for performance calculations.
Just be safe… and keep the blue side up!!!
