Apps Script's Time-Based Triggers: Automating Daily Tasks with Precision

Google Apps Script's time-based triggers don't fire at exact clock times—atHour(8) runs sometime between 8:00 and 9:00 AM depending on infrastructure batching. Understanding this timing uncertainty, managing duplicate triggers through proper deletion logic, respecting project-level timezone settings, and building tolerance for trigger execution variance is essential for reliable production automation; when millisecond precision is required, Cloud Scheduler with Cloud Functions is the appropriate alternative.