Trying to get Last Snow from sensor open weather prec kind

I am trying to get how long ago it snowed from sensor.openweathermap_precipitation_kind to place on my weather dashboard. My I have banging my head on this for hours on probably a very easy solution.

Do I need to create trigger like this:

  • trigger:
    • platform: state
      entity_id: sensor.openweathermap_precipitation_kind
      from: ‘Snow’
      sensor:
    • name: last_snow
      state: "{{ now().timestamp() | timestamp_custom(‘%I:%M %p %a’) }} "

Thanks in advanced