The newer sun triggers in Home Assistant, such as sun.sunset, and the calendar triggers for an event start and end have so far stored the offset as two fields: a duration and an offset_type of before or after. Pull request #184855, merged into the development branch on 23 October 2026 and marked as a breaking change, replaces them with one signed offset. It is due in Home Assistant 2026.11.
What changes
A negative offset now fires before the event and a positive one after it. The change covers the sun event triggers, from sunrise, sunset, dawn and dusk to the start and end of golden and blue hour, and the calendar.event_started and calendar.event_ended triggers.
Before:
trigger: sun.sunset
options:
offset:
minutes: 30
offset_type: before
After:
trigger: sun.sunset
options:
offset:
minutes: -30
In the automation editor you no longer set a separate type. The offset field itself lets you choose no offset, before or after. This uses a new offset mode of the duration selector, added on 2 October 2026 in #181884, which also offers a signed mode with a plus or minus picker. Blueprints that use allow_negative: true keep working, because that option is now an alias for the signed mode.
Who has to edit YAML
Existing triggers that have offset_type keep working. Home Assistant reads the old field and turns it into the right sign, so everything created in the UI is safe, because the editor always wrote offset_type.
The risk is in triggers written by hand in YAML with an offset but without offset_type. They used to default to before, so a positive offset fired before the event. From 2026.11 the same value fires after it. If a "30 minutes before sunset" automation of yours has only offset: {minutes: 30} and no type, change it to -30. Otherwise the lights will come on an hour later than you expect, half an hour after sunset instead of half an hour before.
The classic sun trigger in the trigger: sun with event: sunset form is not affected. It has always used a signed offset, for example offset: "-00:30:00".