Cron on March 15th at 9 AM

The cron expression 0 9 15 3 * schedules a task to run once per year on March 15th at exactly 9:00 AM.

Field-by-field breakdown:

• 0 (Minute): At minute 0. The task fires at the top of the hour.
• 9 (Hour): At hour 9 (9 AM). The task runs at the start of the business day.
• 15 (Day of Month): On the 15th day of the month only.
• 3 (Month): In March only. Combined with day 15, this targets the Ides of March, which is also a significant date in many business calendars.
• * (Day of Week): Every day of the week. No restriction on the day of the week.

This means your task will execute exactly once per year, at 9:00 AM on March 15th. This date is significant in several contexts: it is the deadline for various tax-related filings in multiple countries, marks the midpoint of Q1 for fiscal years starting in January, and is commonly used for annual compliance deadlines. Fixed annual dates are useful for triggering deadline reminders, generating compliance reports, initiating annual review processes, or rotating annual security credentials. You can adapt this pattern for any specific annual date by changing the day and month fields accordingly. This expression is supported by standard cron on Linux/macOS, as well as cloud services like AWS CloudWatch, Google Cloud Scheduler, and GitHub Actions.