Why Your Automations Stop Working After Daylight Saving — and the Fix

3. The Scheduling Algorithm Breakdown

Most automation platforms rely on scheduling algorithms that assume time progresses in a predictable, linear fashion, making them vulnerable to the temporal anomalies created by daylight saving transitions. Traditional cron-style schedulers, which form the backbone of many automation systems, use simple time-based patterns that don't account for the possibility of missing or duplicated hours. When spring forward occurs and 2:00 AM becomes 3:00 AM instantly, any automation scheduled to run at 2:30 AM simply cannot execute because that time doesn't exist. Conversely, during fall back transitions when 2:00 AM occurs twice, schedulers may either run automations twice or become confused about which instance of the duplicated hour they should use as a reference. The algorithms that calculate "next run time" often fail to properly handle these edge cases, leading to calculations that point to impossible times or create infinite loops as the system tries to schedule events in the temporal gap. Advanced scheduling systems attempt to address these issues through various strategies, but many legacy systems and simpler automation platforms continue to use naive time calculations that break down during daylight saving transitions.