diff --git a/.cron.yml b/.cron.yml
index 24d107e03..fdc0e07ac 100644
--- a/.cron.yml
+++ b/.cron.yml
@@ -9,8 +9,9 @@ jobs:
           type: decision-task
           treeherder-symbol: Nd
           target-tasks-method: nightly
-      when: [{hour: 6, minute: 0}]
-      when: [{hour: 18, minute: 0}]
+      when:
+          - {hour: 6, minute: 0}
+          - {hour: 18, minute: 0}
     - name: raptor
       job:
           type: decision-task