Scheduling with timetables

For a Dag with a time-based schedule, the internal timetable drives scheduling and determines the data interval and logical date of each created run; cron expressions and timedelta objects are internally converted to timetables. Trigger timetables (CronTriggerTimetable, DeltaTriggerTimetable) do not include a data interval, so data_interval_start equals data_interval_end at trigger time; data interval timetables (CronDataIntervalTimetable, DeltaDataIntervalTimetable) set data_interval_end to the trigger time and data_interval_start to the interval start. Both kinds trigger runs at the same time, but run_id timestamps differ because run_id is based on logical_date. Switching an existing Dag from a trigger to a data interval timetable skips one scheduled run; the reverse does not. AssetOrTimeSchedule combines asset events with time-based schedules. Scope: Apache Airflow. Reviewed October 4, 2026.