Ticket #46483: settings-dst-detection.patch

src/wp-admin/options-general.php

@@ -252 +252 @@
 <p class="timezone-info">
 <span>
         <?php
-        // Set TZ so localtime works.
-        date_default_timezone_set( $tzstring );
-        $now = localtime( time(), true );
-        if ( $now['tm_isdst'] ) {
+        $now = new DateTime( 'now', new DateTimeZone( $tzstring ) );
+        $dst = (bool) $now->format( 'I' );
+
+        if ( $dst ) {
                 _e( 'This timezone is currently in daylight saving time.' );
         } else {
                 _e( 'This timezone is currently in standard time.' );
@@ -296 +296 @@
                         _e( 'This timezone does not observe daylight saving time.' );
                 }
         }
-        // Set back to UTC.
-        date_default_timezone_set( 'UTC' );
         ?>
         </span>
 </p>