diff --git a/addons/web/static/src/legacy/js/core/session.js b/addons/web/static/src/legacy/js/core/session.js
index 0ba3b5160a3..76e062a6798 100644
--- a/addons/web/static/src/legacy/js/core/session.js
+++ b/addons/web/static/src/legacy/js/core/session.js
@@ -305,7 +305,7 @@ var Session = core.Class.extend(mixins.EventDispatcherMixin, {
      * @returns {integer}
      */
     getTZOffset: function (date) {
-        return -new Date(date).getTimezoneOffset();
+        return -new Date(new Date(date).toISOString().replace('Z', '')).getTimezoneOffset();
     },
     //--------------------------------------------------------------------------
     // Public