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

4. API Communication Failures Across Time Zones

Modern automations rarely operate in isolation; they typically involve multiple systems communicating through APIs, each potentially operating in different time zones with varying daylight saving rules. During daylight saving transitions, these inter-system communications can experience catastrophic failures when timestamp mismatches occur. Consider an automation that triggers a workflow in System A, which then sends a timestamped request to System B in a different timezone. If System A has updated for daylight saving but System B hasn't (or vice versa), the timestamps become misaligned, potentially causing the receiving system to reject requests as being from the future or too far in the past. This temporal desynchronization can cascade through entire automation chains, where each system in the sequence becomes increasingly confused about the actual time. Authentication systems are particularly vulnerable, as many security protocols rely on timestamp validation to prevent replay attacks. When daylight saving creates timestamp discrepancies, legitimate automation requests may be flagged as security threats and blocked, causing workflows to fail mysteriously. The problem is compounded when systems use different time representations (UTC vs. local time) or have varying levels of precision in their timestamp handling.