Openweather cloud cover forecast

I am trying to show the forecast cloud cover using Openweather and cannot find the array name for this.

I have worked out how to get the forecast temperature - here is the example for the forecast at 15.00:

    forecast_temp_15:
      friendly_name: "Temp at 15.00"
      value_template: >
        {% set sensor_trigger = states('sensor.time') %}
        {% set current_hr = now().strftime("%H")|int %}
        {% set sensor_hr = 15 %}
        {% set array_no = sensor_hr - current_hr if current_hr <= sensor_hr else 24-current_hr + sensor_hr %}
        {{ state_attr('weather.openweathermap', 'forecast') [array_no] ['temperature'] }}

However I cannot find the array name for cloud cover. I have tried ‘cloud_cover’, ‘clouds’, ‘forecast_clouds_unit’ but none of these are recognised.

Is there a way of getting weather.openweathermap to list the names of all the array headings?
As an additional piece of helpful advice, is there a way of creating a template sensor that can extract the hour wanted from the sensor heading (ie extract 15.00 from forecast_temp_15) and put it into the variable sensor_hr ?
Thank you very much for your help.

I just started to look into OWM a bit better, I cannot find any cloud related data in the forecast…hence your logic will not work I guess. Or, am I wrong, does your OWM entity show cloud data in the forecast?
I just created a PR to add humidity to the forecast and may add this too … but I need to know if OWM actually provides this and how, check this post
OpenWeatherMap Hourly Forecast - Humidity missing - Feature Requests - Home Assistant Community (home-assistant.io)