diff --git a/scripts/generate_reports.py b/scripts/generate_reports.py
index 178951e..118d2dc 100644
--- a/scripts/generate_reports.py
+++ b/scripts/generate_reports.py
@@ -3,7 +3,7 @@ import sqlite3
 from pathlib import Path
 import shutil
 from typing import List, Dict, Optional
-from datetime import datetime
+from datetime import datetime, timezone
 import time
 
 import yaml
@@ -37,7 +37,8 @@ def _cli_callback(ctx: typer.Context) -> None:
 
     def _write_marker() -> None:
         OUTPUT_DIR.mkdir(parents=True, exist_ok=True)
-        timestamp = datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S")
+        # Use timezone-aware UTC to avoid deprecation warnings and ambiguity
+        timestamp = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
         GENERATED_MARKER.write_text(f"{timestamp}\n")
 
     ctx.call_on_close(_write_marker)
@@ -271,7 +272,8 @@ def _generate_global() -> None:
         return
 
     start_time = time.time()
-    generated_at = datetime.utcnow().strftime("%Y-%m-%d %H:%M:%S")
+    # Use timezone-aware UTC for generated_at (string remains unchanged format)
+    generated_at = datetime.now(timezone.utc).strftime("%Y-%m-%d %H:%M:%S")
 
     _copy_icons()