illuminance.yaml

# pnbruckner's sensor component as a template.
# https://github.com/pnbruckner/ha-illuminance/blob/master/custom_components/illuminance/sensor.py
# https://community.home-assistant.io/t/outdoor-illuminance-estimated-from-weather-conditions-reported-by-weather-underground-dark-sky-or-yr-no/
# https://community.home-assistant.io/t/outdoor-illuminance-template-sensor/

sensor:
  - platform: template
    sensors:
      illuminance:
        friendly_name: Outdoor Illuminance Educated Guessor
        icon_template: mdi:brightness-auto
        unit_of_measurement: lx
        value_template: |
          {%- set factors = namespace(condition='',sun='') %}

          {#- Retrieve the current condition and normalize the value #}
          {%- set current_condition = states("weather.kariong") %}
          {%- set current_condition = current_condition|lower|replace("-day","")|replace("_day","")|replace("-night","")|replace("_night","")|replace("and","")|replace("-", " ")|replace("_", " ")|replace("(","")|replace(")","")|replace(".", "")|replace(" ", "") %}

          
          {#- Assign a seemingly arbitrary number to the condition factor #}
          {%- set condition_factors = {
            "10000": ("clear", "clearnight", "sunny", "windy", "wind", "windyvariant", "exceptional"),
            "7500": ("partlycloudy", "partlysunny", "mostlysunny", "mostlyclear", "hazy", "hazey", "hazysunshine", "intermittentclouds", "lightrain"),
            "2500": ("cloudy", "mostlycloudy"),
            "1000": ("fog", "foggy", "dust", "dusty", "rainy", "rain", "lightshower", "lightshowers", "showers", "shower", "snowy", "snow", "snowyheavy", "snowyrainy", "flurries", "chanceflurries", "chancerain", "chancesleet", "drearyovercast", "sleet", "frost"),
            "200": ("hail", "lightning", "tstorms", "thunderstorm", "storm", "stormy", "heavyshower", "heavyshowers", "tropicalcyclone")
          } %}
          {%- for factor in condition_factors if current_condition in condition_factors[factor] %}
            {%- set factors.condition = factor %}
          {%- endfor %}
          
          {#- Compute Sun Factor #}
          {%- set right_now = now() | as_timestamp %}
          {%- set sunrise = states("sensor.solar_sunrise") | as_timestamp %}
          {%- set sunrise_begin = states("sensor.solar_dawn") | as_timestamp %}
          {%- set sunrise_end = sunrise + (40 * 60) %}
          {%- set sunset = states("sensor.solar_sunset") | as_timestamp %}
          {%- set sunset_begin = sunset - (40 * 60) %}
          {%- set sunset_end = states("sensor.solar_dusk") | as_timestamp %}
          {%- if sunrise_end < right_now and right_now < sunset_begin %}
            {%- set factors.sun = 1 %}
          {%- elif sunset_end < right_now or right_now < sunrise_begin %}
            {%- set factors.sun = 0 %}
          {%- elif right_now <= sunrise_end %}
            {%- set factors.sun = (right_now - sunrise_begin) / (60*60) %}
          {%- else %}
            {%- set factors.sun = (sunset_end - right_now) / (60*60) %}
          {%- endif %}
          {%- set factors.sun = 1 if factors.sun > 1 else factors.sun %}
          
          {# Take an educated guess #}
          {%- set illuminance = (factors.sun|float * factors.condition|float) | round %}
          {%- set illuminance = 10 if illuminance < 10 else illuminance %}
          {{ illuminance }}
 
 # Use PBruckner Component
  - platform: illuminance
    entity_id: weather.home
    name: Estimated Illuminance