Index: src/wp-admin/options-general.php
IDEA additional info:
Subsystem: com.intellij.openapi.diff.impl.patch.CharsetEP
<+>UTF-8
===================================================================
--- src/wp-admin/options-general.php	(date 1558926153000)
+++ src/wp-admin/options-general.php	(date 1558964035095)
@@ -252,10 +252,10 @@
 <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.' );
@@ -296,8 +296,6 @@
 			_e( 'This timezone does not observe daylight saving time.' );
 		}
 	}
-	// Set back to UTC.
-	date_default_timezone_set( 'UTC' );
 	?>
 	</span>
 </p>