Timezone incidents are often dismissed as "calendar mistakes," but they are operational failures with recurring root causes. This template helps teams diagnose why a cross-region miss happened and prevent it from repeating.
When to Use This Template
- Customers or stakeholders missed a meeting due to timezone confusion.
- A launch notification used ambiguous local time format.
- DST transition caused wrong on-call or handoff assumptions.
- Regional teams interpreted "same-day" differently around the date line.
Original RCA Lens: T-MAP
Classify the incident using T-MAP to improve pattern detection:
- T (Time Expression): Was the time notation ambiguous?
- M (Mechanism): Which system converted or displayed time incorrectly?
- A (Assumption): What human assumption went unverified?
- P (Process): Which checklist or review gate was missing?
Copy-Paste Postmortem Template
INCIDENT NAME:
INCIDENT DATE (UTC):
SEVERITY:
AFFECTED REGIONS:
1) WHAT HAPPENED
- Summary:
- Customer/Team impact:
2) TIMELINE (ALL ENTRIES IN UTC + LOCAL)
- Detection time:
- Escalation time:
- Resolution time:
3) T-MAP ANALYSIS
- Time expression issue:
- Mechanism issue:
- Assumption issue:
- Process issue:
4) ROOT CAUSE
- Primary cause:
- Contributing causes:
5) CORRECTIVE ACTIONS
- Immediate fixes (0-7 days):
- Systemic fixes (8-45 days):
- Owner and due date for each action:
6) PREVENTION CONTROLS
- Canonical time format standard:
- DST transition checklist owner:
- Cross-region confirmation rule:
Definition of Done for Timezone Incidents
An incident is only resolved when preventive controls are deployed and observed in at least two future cross-region events without recurrence.
Suggested Controls You Can Adopt Today
- Always publish UTC alongside local time in customer-facing updates.
- Enforce canonical links and standard timezone labels in all templates.
- Run DSA-48 before and after DST transitions.
- Require one independent reviewer for any global event announcement.