diff --git a/core/modules/locale/locale.datepicker.js b/core/modules/locale/locale.datepicker.js
index 4628eda..7b0dd02 100644
--- a/core/modules/locale/locale.datepicker.js
+++ b/core/modules/locale/locale.datepicker.js
@@ -75,6 +75,7 @@
           Drupal.t('Fr'),
           Drupal.t('Sa')
         ],
+        weekHeader: Drupal.t('Wk'),
         dateFormat: Drupal.t('mm/dd/yy'),
         firstDay: 0,
         isRTL: 0