diff --git a/core/modules/system/lib/Drupal/system/Tests/Datetime/DrupalDateTimeTest.php b/core/modules/system/lib/Drupal/system/Tests/Datetime/DrupalDateTimeTest.php
index 9673c9c65caa57848d87ed6b4bdd3e2772aa4741..3707bf88a38be0eb4803334c38004805fac6232a 100644
--- a/core/modules/system/lib/Drupal/system/Tests/Datetime/DrupalDateTimeTest.php
+++ b/core/modules/system/lib/Drupal/system/Tests/Datetime/DrupalDateTimeTest.php
@@ -36,6 +36,20 @@ public function setUp() {
 
   }
 
+  /**
+   * Test that the AJAX Timezone Callback can deal with various formats.
+   */
+  public function testSystemTimezone() {
+    $options = array(
+      'query' => array(
+        'date' => 'Tue+Sep+17+2013+21%3A35%3A31+GMT%2B0100+(BST)#',
+      )
+    );
+    // Query the AJAX Timezone Callback with a long-format date.
+    $response = $this->drupalGet('system/timezone/BST/3600/1', $options);
+    $this->assertEqual($response, '"Europe\/London"', 'Timezone AJAX callback successfully identifies and responds to a long-format date.');
+  }
+
   /**
    * Test that DrupalDateTime can detect the right timezone to use.
    * Test with a variety of less commonly used timezone names to
diff --git a/core/modules/system/system.routing.yml b/core/modules/system/system.routing.yml
index d759cf313975ab61e2de351d79ac800a2882aadb..4d1c90ac29f171b4ee56825d091fa1dd5a34bc6f 100644
--- a/core/modules/system/system.routing.yml
+++ b/core/modules/system/system.routing.yml
@@ -344,9 +344,12 @@ system.modules_uninstall_confirm:
     _permission: 'administer modules'
 
 system.timezone:
-  path: '/system/timezone'
+  path: '/system/timezone/{abbreviation}/{offset}/{is_daylight_saving_time}'
   defaults:
     _controller: '\Drupal\system\Controller\TimezoneController::getTimezone'
+    abbreviation: ''
+    offset: -1
+    is_daylight_saving_time: NULL
   requirements:
     _access: 'TRUE'