diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 79d980c2..6e548fc3 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -6,6 +6,8 @@ on:
       - main
     tags:
       - v*.*.*
+  schedule:
+    - cron: 14 21 * * *
 
 concurrency:
   group: ${{ github.ref }}
@@ -55,6 +57,9 @@ jobs:
           # TruffleRuby doesn't work on Windows.
           - os: windows-latest
             ruby: truffleruby-25.0.0
+          # GH282: System Ruby on Windows is no longer working.
+          - os: windows-latest
+            ruby: system
     defaults:
       run:
         working-directory: examples/gem