diff --git a/library/Icinga/Util/TimezoneDetect.php b/library/Icinga/Util/TimezoneDetect.php
index 4967c7f57..03d051366 100644
--- a/library/Icinga/Util/TimezoneDetect.php
+++ b/library/Icinga/Util/TimezoneDetect.php
@@ -3,6 +3,8 @@
 
 namespace Icinga\Util;
 
+use DateTimeZone;
+
 /**
  * Retrieve timezone information from cookie
  */
@@ -15,13 +17,6 @@ class TimezoneDetect
      */
     private static $success;
 
-    /**
-     * Timezone offset in minutes
-     *
-     * @var int
-     */
-    private static $offset = 0;
-
     /**
      * @var string
      */
@@ -34,13 +29,6 @@ class TimezoneDetect
      */
     public static $cookieName = 'icingaweb2-tzo';
 
-    /**
-     * Timezone name
-     *
-     * @var string
-     */
-    private static $timezone;
-
     /**
      * Create new object and try to identify the timezone
      */
@@ -50,31 +38,14 @@ class TimezoneDetect
             return;
         }
 
-        if (array_key_exists(self::$cookieName, $_COOKIE)) {
-            $matches = array();
-            if (preg_match('/\A(-?\d+)[\-,](\d+)\z/', $_COOKIE[self::$cookieName], $matches)) {
-                $offset = $matches[1];
-                $timezoneName = timezone_name_from_abbr('', (int) $offset, (int) $matches[2]);
-
-                self::$success = (bool) $timezoneName;
-                if (self::$success) {
-                    self::$offset = $offset;
-                    self::$timezoneName = $timezoneName;
-                }
-            }
+        if (in_array($_COOKIE[self::$cookieName] ?? null, DateTimeZone::listIdentifiers(), true)) {
+            self::$timezoneName = $_COOKIE[self::$cookieName];
+            self::$success = true;
+        } else {
+            self::$success = false;
         }
     }
 
-    /**
-     * Get offset
-     *
-     * @return int
-     */
-    public function getOffset()
-    {
-        return self::$offset;
-    }
-
     /**
      * Get timezone name
      *
@@ -102,6 +73,5 @@ class TimezoneDetect
     {
         self::$success = null;
         self::$timezoneName = null;
-        self::$offset = 0;
     }
 }
diff --git a/public/js/icinga/timezone.js b/public/js/icinga/timezone.js
index 1c2647bec..c92c57746 100644
--- a/public/js/icinga/timezone.js
+++ b/public/js/icinga/timezone.js
@@ -4,28 +4,6 @@
 
     'use strict';
 
-    /**
-     * Get the maximum timezone offset
-     *
-     * @returns {Number}
-     */
-    Date.prototype.getStdTimezoneOffset = function() {
-        var year = new Date().getFullYear();
-        var offsetInJanuary = new Date(year, 0, 2).getTimezoneOffset();
-        var offsetInJune = new Date(year, 5, 2).getTimezoneOffset();
-
-        return Math.max(offsetInJanuary, offsetInJune);
-    };
-
-    /**
-     * Test for daylight saving time zone
-     *
-     * @returns {boolean}
-     */
-    Date.prototype.isDst = function() {
-        return this.getStdTimezoneOffset() !== this.getTimezoneOffset();
-    };
-
     /**
      * Write timezone information into a cookie
      *
@@ -51,15 +29,11 @@
          * Write timezone information into cookie
          */
         writeTimezone: function() {
-            var date = new Date();
-            var timezoneOffset = (date.getTimezoneOffset()*60) * -1;
-            var dst = date.isDst();
-
             if (this.readCookie(this.cookieName)) {
                 return;
             }
 
-            this.writeCookie(this.cookieName, timezoneOffset + '-' + Number(dst), 1);
+            this.writeCookie(this.cookieName, Intl.DateTimeFormat().resolvedOptions().timeZone);
         },
 
         /**
@@ -67,17 +41,9 @@
          *
          * @param {String} name
          * @param {String} value
-         * @param {Number} days
          */
-        writeCookie: function(name, value, days) {
-            var expires = '';
-
-            if (days) {
-                var date = new Date();
-                date.setTime(date.getTime()+(days*24*60*60*1000));
-                var expires = '; expires=' + date.toGMTString();
-            }
-            document.cookie = name + '=' + value + expires + '; path=/';
+        writeCookie: function(name, value) {
+            document.cookie = name + '=' + value + '; path=/';
         },
 
         /**
diff --git a/test/php/library/Icinga/Util/TimezoneDetectTest.php b/test/php/library/Icinga/Util/TimezoneDetectTest.php
index 9df04720c..7548d4a22 100644
--- a/test/php/library/Icinga/Util/TimezoneDetectTest.php
+++ b/test/php/library/Icinga/Util/TimezoneDetectTest.php
@@ -8,38 +8,42 @@ use Icinga\Util\TimezoneDetect;
 
 class TimezoneDetectTest extends BaseTestCase
 {
-    public function testPositiveTimezoneOffsetSeparatedByComma()
+    public function testInvalidTimezoneNameInCookie(): void
     {
-        $this->assertTimezoneDetection('3600,0', 'Europe/Paris');
+        $tzDetect = new TimezoneDetect();
+        $tzDetect->reset();
+        
+        $_COOKIE[TimezoneDetect::$cookieName] = 'ABC';
+        $tzDetect = new TimezoneDetect();
+        $this->assertFalse(
+            $tzDetect->success(),
+            false,
+            'Failed to assert invalid timezone name is detected'
+        );
+
+        $this->assertNull(
+            $tzDetect->getTimezoneName(),
+            'Failed to assert that the timezone name will not be set for invalid timezone'
+        );
     }
 
-    public function testPositiveTimezoneOffsetSeparatedByHyphen()
-    {
-        $this->assertTimezoneDetection('3600-0', 'Europe/Paris');
-    }
-
-    public function testNegativeTimezoneOffsetSeparatedByComma()
-    {
-        $this->assertTimezoneDetection('-3600,0', 'Atlantic/Azores');
-    }
-
-    public function testNegativeTimezoneOffsetSeparatedByHyphen()
-    {
-        $this->assertTimezoneDetection('-3600-0', 'Atlantic/Azores');
-    }
-
-    protected function assertTimezoneDetection($cookieValue, $expectedTimezoneName)
+    public function testValidTimezoneNameInCookie(): void
     {
         $tzDetect = new TimezoneDetect();
         $tzDetect->reset();
 
-        $_COOKIE[TimezoneDetect::$cookieName] = $cookieValue;
+        $_COOKIE[TimezoneDetect::$cookieName] = "Europe/Berlin";
         $tzDetect = new TimezoneDetect();
+        $this->assertTrue(
+            $tzDetect->success(),
+            true,
+            'Failed to assert that the valid timezone name is detected'
+        );
+
         $this->assertSame(
             $tzDetect->getTimezoneName(),
-            $expectedTimezoneName,
-            'Failed asserting that the timezone "' . $expectedTimezoneName
-            . '" is being detected from the cookie value "' . $cookieValue . '"'
+            "Europe/Berlin",
+            'Failed to assert that the valid timezone name was correctly set'
         );
     }
 }