This is a simple trial automation to fire an automation when an event starts, and when it ends:-
This is the calendar event:-
message: Hot Water
all_day: false
start_time: 2025-09-27 20:15:00
end_time: 2025-09-27 20:20:00
location:
description:
friendly_name: Heating and Hot Water
supported_features: 7
And this is the automation:-
lias: Hot Water Control
description: ""
triggers:
- trigger: calendar
entity_id: calendar.heating_and_hot_water
event: start
offset: "0:0:0"
id: "on"
- trigger: calendar
entity_id: calendar.heating_and_hot_water
event: end
offset: "0:0:0"
id: "off"
conditions:
- condition: template
value_template: "{{ \"hot water\" in trigger.calendar_event.summary|lower }}"
actions:
- action: persistent_notification.create
metadata: {}
data:
message: Hot Water is now {{trigger.id}}
mode: single
I’d previously set up test events that were only a minute long, and found that the event start would trigger, but event end did not. I wondered if the calendar event system wasn’t designed to events that short…
So I set the event up with 5 minutes between the start and end times, but now, neither event start or end trigger the automation, they just did’nt fire at all.
UPDATE:- So google is suggesting that new events made, that are less than 15 minutes from their start time might not fire correctly. Not sure why this is the case when the entity is showing the event data correctly, before the trigger time, but I’ll test that and see what happens.
UPDATE:- Seems giving it more time between the event creation and it then being used as a trigger for an automation has worked.
