diff --git a/src/cron.js b/src/cron.js
index ca40c4c8b..9478f7368 100644
--- a/src/cron.js
+++ b/src/cron.js
@@ -135,7 +135,7 @@ function recreateJobs(tz) {
 
     if (gCleanupBackupsJob) gCleanupBackupsJob.stop();
     gCleanupBackupsJob = new CronJob({
-        cronTime: '00 * * * * *', // every 4 hours
+        cronTime: '00 00 */4 * * *', // every 4 hours
         onTick: backups.cleanup,
         start: true,
         timeZone: tz