diff --git a/modules/periodic.nix b/modules/periodic.nix
index 8e88627..8e388b2 100644
--- a/modules/periodic.nix
+++ b/modules/periodic.nix
@@ -38,7 +38,7 @@
     description = "Monthly purge of Doom Emacs";
     wantedBy = [ "default.target" ];
     timerConfig = {
-      OnCalendar = "13 22:00:00";
+      OnCalendar = "13-*-* 22:00:00";
       Unit = "doom-purge.service";
     };
   };