Index: src/wp-includes/class-wp-locale.php
===================================================================
--- src/wp-includes/class-wp-locale.php	(revision 40036)
+++ src/wp-includes/class-wp-locale.php	(working copy)
@@ -105,6 +105,14 @@
 	public $number_format;
 
 	/**
+	 * Stores the translated strings for some jQuery UI components.
+	 *
+	 * @since 4.8.0
+	 * @var array
+	 */
+	public $jquery_ui_i18n;
+
+	/**
 	 * Constructor which calls helper methods to set up object variables.
 	 *
 	 * @since 2.1.0
@@ -234,6 +242,14 @@
 			$this->text_direction = 'ltr';
 			add_action( 'all_admin_notices', array( $this, 'rtl_src_admin_notice' ) );
 		}
+
+		$this->jquery_ui_i18n = array(
+			'datepicker' => array(
+				'week_header'  => /* translators: header for the jQuery UI datepicker week number column */ _x( 'Wk', 'header for the jQuery UI datepicker week number column' ),
+				'year_suffix'  => /* translators: suffix for the year in the jQuery UI datepicker header */ _x( '', 'suffix for the year in the jQuery UI datepicker header' ),
+				'header_order' => /* translators: 'monthyear' or 'yearmonth'. jQuery UI datepicker header options order. */ _x( 'monthyear', 'jQuery UI datepicker header options order' )
+			)
+		);
 	}
 
 	/**
Index: src/wp-includes/script-loader.php
===================================================================
--- src/wp-includes/script-loader.php	(revision 40036)
+++ src/wp-includes/script-loader.php	(working copy)
@@ -975,18 +975,21 @@
 	);
 
 	$datepicker_defaults = wp_json_encode( array(
-		'closeText'       => __( 'Close' ),
-		'currentText'     => __( 'Today' ),
-		'monthNames'      => array_values( $wp_locale->month ),
-		'monthNamesShort' => array_values( $wp_locale->month_abbrev ),
-		'nextText'        => __( 'Next' ),
-		'prevText'        => __( 'Previous' ),
-		'dayNames'        => array_values( $wp_locale->weekday ),
-		'dayNamesShort'   => array_values( $wp_locale->weekday_abbrev ),
-		'dayNamesMin'     => array_values( $wp_locale->weekday_initial ),
-		'dateFormat'      => $datepicker_date_format,
-		'firstDay'        => absint( get_option( 'start_of_week' ) ),
-		'isRTL'           => $wp_locale->is_rtl(),
+		'closeText'          => __( 'Close' ),
+		'currentText'        => __( 'Today' ),
+		'monthNames'         => array_values( $wp_locale->month ),
+		'monthNamesShort'    => array_values( $wp_locale->month_abbrev ),
+		'nextText'           => __( 'Next' ),
+		'prevText'           => __( 'Previous' ),
+		'dayNames'           => array_values( $wp_locale->weekday ),
+		'dayNamesShort'      => array_values( $wp_locale->weekday_abbrev ),
+		'dayNamesMin'        => array_values( $wp_locale->weekday_initial ),
+		'dateFormat'         => $datepicker_date_format,
+		'firstDay'           => absint( get_option( 'start_of_week' ) ),
+		'isRTL'              => $wp_locale->is_rtl(),
+		'weekHeader'         => $wp_locale->jquery_ui_i18n['datepicker']['week_header'],
+		'yearSuffix'         => $wp_locale->jquery_ui_i18n['datepicker']['year_suffix'],
+		'showMonthAfterYear' => ( 'monthyear' != $wp_locale->jquery_ui_i18n['datepicker']['header_order'] ),
 	) );
 
 	wp_add_inline_script( 'jquery-ui-datepicker', "jQuery(document).ready(function(jQuery){jQuery.datepicker.setDefaults({$datepicker_defaults});});" );