diff --git a/application/controllers/GraphController.php b/application/controllers/GraphController.php
index 644c56a..0c3ea9f 100644
--- a/application/controllers/GraphController.php
+++ b/application/controllers/GraphController.php
@@ -2,13 +2,11 @@
 
 namespace Icinga\Module\Graphite\Controllers;
 
-use DateTimeZone;
 use Icinga\Exception\Http\HttpBadRequestException;
 use Icinga\Exception\Http\HttpNotFoundException;
 use Icinga\Module\Graphite\Graphing\GraphingTrait;
 use Icinga\Module\Graphite\Web\Controller\MonitoringAwareController;
 use Icinga\Module\Graphite\Web\Widget\Graphs;
-use Icinga\Util\TimezoneDetect;
 use Icinga\Web\UrlParams;
 
 class GraphController extends MonitoringAwareController
@@ -110,16 +108,12 @@ class GraphController extends MonitoringAwareController
                 throw new HttpNotFoundException($this->translate('No such graph'));
 
             case 1:
-                $timezoneDetect = new TimezoneDetect();
                 $charts[0]
                     ->setFrom($this->graphParams['start'])
                     ->setUntil($this->graphParams['end'])
                     ->setWidth($this->graphParams['width'])
                     ->setHeight($this->graphParams['height'])
                     ->setShowLegend((bool) $this->graphParams['legend'])
-                    ->setTimeZone(new DateTimeZone(
-                        $timezoneDetect->success() ? $timezoneDetect->getTimezoneName() : date_default_timezone_get()
-                    ))
                     ->serveImage($this->getResponse());
 
             default:
diff --git a/application/forms/TimeRangePicker/CustomForm.php b/application/forms/TimeRangePicker/CustomForm.php
index baafe4f..a190b9d 100644
--- a/application/forms/TimeRangePicker/CustomForm.php
+++ b/application/forms/TimeRangePicker/CustomForm.php
@@ -6,7 +6,6 @@ use DateInterval;
 use DateTime;
 use DateTimeZone;
 use Icinga\Module\Graphite\Web\Form\Decorator\Proxy;
-use Icinga\Util\TimezoneDetect;
 use Icinga\Web\Form;
 
 class CustomForm extends Form
@@ -23,13 +22,6 @@ class CustomForm extends Form
      */
     protected $timestamp = '/^(?:0|-?[1-9]\d*)$/';
 
-    /**
-     * The time zone of all dates and times
-     *
-     * @var DateTimeZone
-     */
-    protected $timeZone;
-
     /**
      * Right now
      *
@@ -164,7 +156,7 @@ class CustomForm extends Form
                 list($date, $time) = explode(
                     'T',
                     DateTime::createFromFormat('U', $timestamp)
-                        ->setTimezone($this->getTimeZone())
+                        ->setTimezone(new DateTimeZone(date_default_timezone_get()))
                         ->format($this->dateTimeFormat)
                 );
 
@@ -209,8 +201,7 @@ class CustomForm extends Form
             $dateTime = DateTime::createFromFormat(
                 $this->dateTimeFormat,
                 ($date === '' ? $this->getNow()->format('Y-m-d') : $date)
-                    . 'T' . ($time === '' ? $defaultTime : $time),
-                $this->getTimeZone()
+                    . 'T' . ($time === '' ? $defaultTime : $time)
             );
 
             if ($dateTime === false) {
@@ -226,36 +217,6 @@ class CustomForm extends Form
         }
     }
 
-    /**
-     * Get {@link timeZone}
-     *
-     * @return DateTimeZone
-     */
-    public function getTimeZone()
-    {
-        if ($this->timeZone === null) {
-            $timezoneDetect = new TimezoneDetect();
-            $this->timeZone = new DateTimeZone(
-                $timezoneDetect->success() ? $timezoneDetect->getTimezoneName() : date_default_timezone_get()
-            );
-        }
-
-        return $this->timeZone;
-    }
-
-    /**
-     * Set {@link timeZone}
-     *
-     * @param DateTimeZone $timeZone
-     *
-     * @return $this
-     */
-    public function setTimeZone(DateTimeZone $timeZone)
-    {
-        $this->timeZone = $timeZone;
-        return $this;
-    }
-
     /**
      * Get {@link now}
      *
@@ -264,7 +225,7 @@ class CustomForm extends Form
     public function getNow()
     {
         if ($this->now === null) {
-            $this->now = (new DateTime())->setTimezone($this->getTimeZone());
+            $this->now = new DateTime();
         }
 
         return $this->now;
diff --git a/library/Graphite/Graphing/Chart.php b/library/Graphite/Graphing/Chart.php
index 1a00862..89d4548 100644
--- a/library/Graphite/Graphing/Chart.php
+++ b/library/Graphite/Graphing/Chart.php
@@ -2,7 +2,6 @@
 
 namespace Icinga\Module\Graphite\Graphing;
 
-use DateTimeZone;
 use Icinga\Module\Graphite\Util\MacroTemplate;
 use Icinga\Web\Response;
 use Icinga\Web\Url;
@@ -66,13 +65,6 @@ class Chart
      */
     protected $showLegend = true;
 
-    /**
-     * The chart's time zone
-     *
-     * @var DateTimeZone
-     */
-    protected $timeZone;
-
     /**
      * Constructor
      *
@@ -118,7 +110,7 @@ class Chart
             'width'                 => $this->width,
             'height'                => $this->height,
             'hideLegend'            => (string) ! $this->showLegend,
-            'tz'                    => $this->timeZone->getName(),
+            'tz'                    => date_default_timezone_get(),
             '_salt'                 => time() . '.000',
             'vTitle'                => 'Percent',
             'lineMode'              => 'connected',
@@ -297,28 +289,4 @@ class Chart
 
         return $this;
     }
-
-    /**
-     * Get time zone
-     *
-     * @return DateTimeZone
-     */
-    public function getTimeZone()
-    {
-        return $this->timeZone;
-    }
-
-    /**
-     * Set time zone
-     *
-     * @param DateTimeZone $timeZone
-     *
-     * @return $this
-     */
-    public function setTimeZone(DateTimeZone $timeZone)
-    {
-        $this->timeZone = $timeZone;
-
-        return $this;
-    }
 }