diff --git a/.github/workflows/docker.yml b/.github/workflows/docker.yml
index 36949e9..69cb434 100644
--- a/.github/workflows/docker.yml
+++ b/.github/workflows/docker.yml
@@ -5,6 +5,9 @@ on:
   push:
     branches:
       - 'master'
+  schedule:
+    # we build monthly at 00:00 on day-of-month 1
+    - cron:  '0 0 1 * *'
 
 jobs:
   docker: