diff --git a/tests/phpunit/tests/date/dateI18n.php b/tests/phpunit/tests/date/dateI18n.php
index 3ffcc54a49..408a4ce447 100644
--- a/tests/phpunit/tests/date/dateI18n.php
+++ b/tests/phpunit/tests/date/dateI18n.php
@@ -89,6 +89,8 @@ class Tests_Date_I18n extends WP_UnitTestCase {
 	 * @ticket 20973
 	 */
 	public function test_date_i18n_handles_shorthand_formats( $short, $full ) {
+		update_option( 'timezone_string', 'America/Regina' );
+
 		$this->assertEquals( strtotime( date_i18n( $full ) ), strtotime( date_i18n( $short ) ), 'The dates should be equal', 2 );
 		$this->assertEquals( $short, date_i18n( '\\' . $short ) );
 	}