home-assistant.io/source/_cookbook/automation_for_rainy_days.markdown

title, description, ha_category

title	description	ha_category
Automation for rainy days	Basic example how to use weather conditions to set states	Automation Examples

This requires a Dark Sky sensor with the condition precip_intensity that tells if it's raining or not. You could also experiment with other attributes such as cloud_cover.

Turn on a light in the living room when it starts raining, someone is home, and it's afternoon or later.

automation:
  - alias: "Rainy Day"
    trigger:
      - platform: state
        entity_id: sensor.precip_intensity
        to: "rain"
    condition:
      - condition: state
        entity_id: all
        state: "home"
      - condition: time
        after: "14:00"
        before: "23:00"
    action:
      service: light.turn_on
      target:
        entity_id: light.couch_lamp

And then of course turn off the lamp when it stops raining but only if it's within an hour before sunset.

  - alias: "Rain is over"
    trigger:
      - platform: state
        entity_id: sensor.precip_intensity
        to: "None"
    condition:
      - condition: sun
        after: "sunset"
        after_offset: "-01:00:00"
    action:
      service: light.turn_off
      target:
        entity_id: light.couch_lamp