HA - Weekly Minimum Temp

wk_min_temp.yaml

template: 
 - trigger:
      - platform: state
        not_to:
          - unknown
          - unavailable
        entity_id: sensor.temp
      - platform: template
        value_template: "{{ now().weekday() == 0 }}"
    action:
      - variables:
          source: "{{ states('sensor.temp') | float }}"
          now: "{{ now() }}"
    sensor:
      - name: Temp Min
        unique_id: ute_temp_min_v
        unit_of_measurement: "°C"
        device_class: temperature
        icon: mdi:thermometer-chevron-down
        state: |
          {% set current = (this.state or trigger.to_state.state) | float(source) %}
          {{ source if trigger.platform == 'template' else [source, current] | min }}
        attributes:
          datetime: |
            {% set current = (this.state or trigger.to_state.state) | float(source) %}
            {{ now if (trigger.platform == 'template' or source < current) else this.attributes.datetime|default(now) }}

EDIT: Corrected issue with this variable use in action block.