diff --git a/lib/Cake/Test/Case/Utility/CakeTimeTest.php b/lib/Cake/Test/Case/Utility/CakeTimeTest.php
index b358b1b48..4bc9f8a62 100644
--- a/lib/Cake/Test/Case/Utility/CakeTimeTest.php
+++ b/lib/Cake/Test/Case/Utility/CakeTimeTest.php
@@ -421,6 +421,18 @@ class CakeTimeTest extends CakeTestCase {
 		$this->_restoreSystemTimezone();
 	}
 
+	public function testNiceTimezoneConversion() {
+		date_default_timezone_set('Europe/Copenhagen'); // server timezone
+		$clientTimeZone = new DateTimeZone('Asia/Bangkok');
+		$clientDateTime = new DateTime('2019-01-31 10:00:00', $clientTimeZone);
+		// Convert to UTC.
+		$actual = CakeTime::nice($clientDateTime, 'UTC', '%Y-%m-%d %H:%M:%S');
+		$clientDateTime->setTimezone(new DateTimeZone('UTC'));
+		$expected = $clientDateTime->format('Y-m-d H:i:s');
+		$this->assertEquals($expected, $actual);
+		$this->_restoreSystemTimezone();
+	}
+
 /**
  * testNiceShort method
  *
@@ -966,23 +978,44 @@ class CakeTimeTest extends CakeTestCase {
  */
 	public function testFromStringWithDateTime() {
 		date_default_timezone_set('UTC');
-
 		$date = new DateTime('+1 hour', new DateTimeZone('America/New_York'));
 		$result = $this->Time->fromString($date, 'UTC');
 		$date->setTimezone(new DateTimeZone('UTC'));
 		$expected = $date->format('U') + $date->getOffset();
-
 		$this->assertWithinMargin($expected, $result, 1);
+		$this->_restoreSystemTimezone();
+	}
 
+	public function testFromStringWithDateTimeAsia() {
 		date_default_timezone_set('Australia/Melbourne');
-
 		$date = new DateTime('+1 hour', new DateTimeZone('America/New_York'));
 		$result = $this->Time->fromString($date, 'Asia/Kuwait');
-
 		$date->setTimezone(new DateTimeZone('Asia/Kuwait'));
 		$expected = $date->format('U') + $date->getOffset();
 		$this->assertWithinMargin($expected, $result, 1);
+		$this->_restoreSystemTimezone();
+	}
 
+	public function testFromStringTimezoneConversionToUTC() {
+		date_default_timezone_set('Europe/Copenhagen'); // server timezone
+		$clientTimeZone = new DateTimeZone('Asia/Bangkok');
+		$clientDateTime = new DateTime('2019-01-31 10:00:00', $clientTimeZone);
+		// Convert to UTC.
+		$actual = CakeTime::fromString($clientDateTime, 'UTC');
+		$clientDateTime->setTimezone(new DateTimeZone('UTC'));
+		$expected = $clientDateTime->getTimestamp() + $clientDateTime->getOffset(); // 1548903600
+		$this->assertEquals($expected, $actual);
+		$this->_restoreSystemTimezone();
+	}
+
+	public function testFromStringUTCtoCopenhagen() {
+		date_default_timezone_set('UTC'); // server timezone
+		$clientTimeZone = new DateTimeZone('UTC');
+		$clientDateTime = new DateTime('2012-01-01 10:00:00', $clientTimeZone);
+		$actual = CakeTime::fromString($clientDateTime, 'Europe/Copenhagen');
+		$clientDateTime->setTimezone(new DateTimeZone('Europe/Copenhagen'));
+		$expected = $clientDateTime->getTimestamp() + $clientDateTime->getOffset(); // 1325415600
+		$this->assertEquals($expected, $actual);
 		$this->_restoreSystemTimezone();
 	}
 
@@ -998,6 +1031,24 @@ class CakeTimeTest extends CakeTestCase {
 		$this->assertEquals($result, $date->format('U'));
 	}
 
+	public function testConvertToBangkok() {
+		$serverTimeZoneName = 'Europe/Copenhagen';
+		date_default_timezone_set($serverTimeZoneName);
+
+		$serverTimeZone = new DateTimeZone($serverTimeZoneName);
+		$DateTime = new DateTime('2019-01-31 04:00:00', $serverTimeZone);
+		$serverTimestamp = $DateTime->getTimestamp() + $DateTime->getOffset(); // 1548907200
+
+		$clientTimeZoneName = 'Asia/Bangkok';
+		$clientTimeZone = new DateTimeZone($clientTimeZoneName);
+		$DateTime->setTimezone($clientTimeZone);
+		$expected = $DateTime->getTimestamp() + $DateTime->getOffset(); // 1548928800
+
+		$actual = CakeTime::convert($serverTimestamp, $clientTimeZoneName);
+		$this->assertEquals($expected, $actual);
+		$this->_restoreSystemTimezone();
+	}
+
 /**
  * test converting time specifiers using a time definition localfe file
  *
@@ -1149,6 +1200,28 @@ class CakeTimeTest extends CakeTestCase {
 		$this->assertEquals($expected, $result);
 	}
 
+	public function testI18nFormatTimezoneConversionToUTC() {
+		date_default_timezone_set('Europe/Copenhagen'); // server timezone
+		$clientTimeZone = new DateTimeZone('Asia/Bangkok');
+		$clientDateTime = new DateTime('2019-01-31 10:00:00', $clientTimeZone);
+		// Convert to UTC.
+		$actual = CakeTime::i18nFormat($clientDateTime, '%Y-%m-%d %H:%M:%S', false, 'UTC');
+		$clientDateTime->setTimezone(new DateTimeZone('UTC'));
+		$expected = $clientDateTime->format('Y-m-d H:i:s');
+		$this->assertEquals($expected, $actual);
+		$this->_restoreSystemTimezone();
+	}
+
+	public function testI18nFormatUTCtoCopenhagen() {
+		date_default_timezone_set('UTC');
+		$clientTimeZone = new DateTimeZone('UTC');
+		$clientDateTime = new DateTime('2012-01-01 10:00:00', $clientTimeZone);
+		$actual = CakeTime::i18nFormat($clientDateTime, '%Y-%m-%d %H:%M', false, 'Europe/Copenhagen');
+		$clientDateTime->setTimezone(new DateTimeZone('Europe/Copenhagen'));
+		$expected = $clientDateTime->format('Y-m-d H:i');
+		$this->assertEquals($expected, $actual);
+	}
+
 /**
  * test new format() syntax which inverts first and second parameters
  *
@@ -1217,7 +1290,7 @@ class CakeTimeTest extends CakeTestCase {
  *
  * @return void
  */
-	public function testCorrectTimezoneConversion() {
+	public function testCorrectTimezoneConversionAsString() {
 		date_default_timezone_set('UTC');
 		$date = '2012-01-01 10:00:00';
 		$converted = CakeTime::format($date, '%Y-%m-%d %H:%M', '', 'Europe/Copenhagen');
@@ -1226,4 +1299,27 @@ class CakeTimeTest extends CakeTestCase {
 		$this->assertEquals($expected->format('Y-m-d H:i'), $converted);
 	}
 
+	public function testCorrectTimezoneConversionAsObject() {
+		date_default_timezone_set('UTC');
+		$clientTimeZone = new DateTimeZone('UTC');
+		$date = '2012-01-01 10:00:00';
+		$clientDateTime = new DateTime($date, $clientTimeZone);
+		$converted = CakeTime::format($clientDateTime, '%Y-%m-%d %H:%M', '', 'Europe/Copenhagen');
+		$clientDateTime->setTimezone(new DateTimeZone('Europe/Copenhagen'));
+		$expected = $clientDateTime->format('Y-m-d H:i');
+		$this->assertEquals($expected, $converted);
+	}
+
+	public function testFormatTimezoneConversionToUTC() {
+		date_default_timezone_set('Europe/Copenhagen'); // server timezone
+		$clientTimeZone = new DateTimeZone('Asia/Bangkok');
+		$clientDateTime = new DateTime('2019-01-31 10:00:00', $clientTimeZone);
+		// Convert to UTC.
+		$actual = CakeTime::format($clientDateTime, '%Y-%m-%d %H:%M:%S', false, 'UTC');
+		$clientDateTime->setTimezone(new DateTimeZone('UTC'));
+		$expected = $clientDateTime->format('Y-m-d H:i:s');
+		$this->assertEquals($expected, $actual);
+		$this->_restoreSystemTimezone();
+	}
+
 }
diff --git a/lib/Cake/Utility/CakeTime.php b/lib/Cake/Utility/CakeTime.php
index 2a1de55f3..63911bfde 100644
--- a/lib/Cake/Utility/CakeTime.php
+++ b/lib/Cake/Utility/CakeTime.php
@@ -239,9 +239,9 @@ class CakeTime {
 /**
  * Converts given time (in server's time zone) to user's local time, given his/her timezone.
  *
- * @param string $serverTime UNIX timestamp
- * @param string|DateTimeZone $timezone User's timezone string or DateTimeZone object
- * @return int UNIX timestamp
+ * @param int $serverTime Server's timestamp.
+ * @param string|DateTimeZone $timezone User's timezone string or DateTimeZone object.
+ * @return int User's timezone timestamp.
  * @link https://book.cakephp.org/2.0/en/core-libraries/helpers/time.html#TimeHelper::convert
  */
 	public static function convert($serverTime, $timezone) {
@@ -303,11 +303,11 @@ class CakeTime {
 	}
 
 /**
- * Returns a UNIX timestamp, given either a UNIX timestamp or a valid strtotime() date string.
+ * Returns a timestamp, given either a UNIX timestamp or a valid strtotime() date string.
  *
  * @param int|string|DateTime $dateString UNIX timestamp, strtotime() valid string or DateTime object
  * @param string|DateTimeZone $timezone Timezone string or DateTimeZone object
- * @return string Parsed timestamp
+ * @return int|false Parsed given timezone timestamp.
  * @link https://book.cakephp.org/2.0/en/core-libraries/helpers/time.html#TimeHelper::fromString
  */
 	public static function fromString($dateString, $timezone = null) {
@@ -354,22 +354,22 @@ class CakeTime {
  * See http://php.net/manual/en/function.strftime.php for information on formatting
  * using locale strings.
  *
- * @param int|string|DateTime $dateString UNIX timestamp, strtotime() valid string or DateTime object
+ * @param int|string|DateTime $date UNIX timestamp, strtotime() valid string or DateTime object
  * @param string|DateTimeZone $timezone Timezone string or DateTimeZone object
  * @param string $format The format to use. If null, `CakeTime::$niceFormat` is used
  * @return string Formatted date string
  * @link https://book.cakephp.org/2.0/en/core-libraries/helpers/time.html#TimeHelper::nice
  */
-	public static function nice($dateString = null, $timezone = null, $format = null) {
-		if (!$dateString) {
-			$dateString = time();
+	public static function nice($date = null, $timezone = null, $format = null) {
+		if (!$date) {
+			$date = time();
 		}
-		$date = static::fromString($dateString, $timezone);
-
+		$timestamp = static::fromString($date, $timezone);
 		if (!$format) {
 			$format = static::$niceFormat;
 		}
-		return static::_strftime(static::convertSpecifiers($format, $date), $date);
+		$convertedFormat = static::convertSpecifiers($format, $timestamp);
+		return static::_strftimeWithTimezone($convertedFormat, $timestamp, $date, $timezone);
 	}
 
 /**
@@ -382,28 +382,31 @@ class CakeTime {
  * If $dateString's year is the current year, the returned string does not
  * include mention of the year.
  *
- * @param int|string|DateTime $dateString UNIX timestamp, strtotime() valid string or DateTime object
+ * @param int|string|DateTime $date UNIX timestamp, strtotime() valid string or DateTime object
  * @param string|DateTimeZone $timezone Timezone string or DateTimeZone object
  * @return string Described, relative date string
  * @link https://book.cakephp.org/2.0/en/core-libraries/helpers/time.html#TimeHelper::niceShort
  */
-	public static function niceShort($dateString = null, $timezone = null) {
-		if (!$dateString) {
-			$dateString = time();
+	public static function niceShort($date = null, $timezone = null) {
+		if (!$date) {
+			$date = time();
 		}
-		$date = static::fromString($dateString, $timezone);
+		$timestamp = static::fromString($date, $timezone);
 
-		if (static::isToday($dateString, $timezone)) {
-			return __d('cake', 'Today, %s', static::_strftime("%H:%M", $date));
+		if (static::isToday($date, $timezone)) {
+			$formattedDate = static::_strftimeWithTimezone("%H:%M", $timestamp, $date, $timezone);
+			return __d('cake', 'Today, %s', $formattedDate);
 		}
-		if (static::wasYesterday($dateString, $timezone)) {
-			return __d('cake', 'Yesterday, %s', static::_strftime("%H:%M", $date));
+		if (static::wasYesterday($date, $timezone)) {
+			$formattedDate = static::_strftimeWithTimezone("%H:%M", $timestamp, $date, $timezone);
+			return __d('cake', 'Yesterday, %s', $formattedDate);
 		}
-		if (static::isTomorrow($dateString, $timezone)) {
-			return __d('cake', 'Tomorrow, %s', static::_strftime("%H:%M", $date));
+		if (static::isTomorrow($date, $timezone)) {
+			$formattedDate = static::_strftimeWithTimezone("%H:%M", $timestamp, $date, $timezone);
+			return __d('cake', 'Tomorrow, %s', $formattedDate);
 		}
 
-		$d = static::_strftime("%w", $date);
+		$d = static::_strftimeWithTimezone("%w", $timestamp, $date, $timezone);
 		$day = array(
 			__d('cake', 'Sunday'),
 			__d('cake', 'Monday'),
@@ -413,18 +416,21 @@ class CakeTime {
 			__d('cake', 'Friday'),
 			__d('cake', 'Saturday')
 		);
-		if (static::wasWithinLast('7 days', $dateString, $timezone)) {
-			return sprintf('%s %s', $day[$d], static::_strftime(static::$niceShortFormat, $date));
+		if (static::wasWithinLast('7 days', $date, $timezone)) {
+			$formattedDate = static::_strftimeWithTimezone(static::$niceShortFormat, $timestamp, $date, $timezone);
+			return sprintf('%s %s', $day[$d], $formattedDate);
 		}
-		if (static::isWithinNext('7 days', $dateString, $timezone)) {
-			return __d('cake', 'On %s %s', $day[$d], static::_strftime(static::$niceShortFormat, $date));
+		if (static::isWithinNext('7 days', $date, $timezone)) {
+			$formattedDate = static::_strftimeWithTimezone(static::$niceShortFormat, $timestamp, $date, $timezone);
+			return __d('cake', 'On %s %s', $day[$d], $formattedDate);
 		}
 
 		$y = '';
-		if (!static::isThisYear($date)) {
+		if (!static::isThisYear($timestamp)) {
 			$y = ' %Y';
 		}
-		return static::_strftime(static::convertSpecifiers("%b %eS{$y}, %H:%M", $date), $date);
+		$format = static::convertSpecifiers("%b %eS{$y}, %H:%M", $timestamp);
+		return static::_strftimeWithTimezone($format, $timestamp, $date, $timezone);
 	}
 
 /**
@@ -1055,17 +1061,18 @@ class CakeTime {
  * @link https://book.cakephp.org/2.0/en/core-libraries/helpers/time.html#TimeHelper::i18nFormat
  */
 	public static function i18nFormat($date, $format = null, $default = false, $timezone = null) {
-		$date = static::fromString($date, $timezone);
-		if ($date === false && $default !== false) {
+		$timestamp = static::fromString($date, $timezone);
+		if ($timestamp === false && $default !== false) {
 			return $default;
 		}
-		if ($date === false) {
+		if ($timestamp === false) {
 			return '';
 		}
 		if (empty($format)) {
 			$format = '%x';
 		}
-		return static::_strftime(static::convertSpecifiers($format, $date), $date);
+		$convertedFormat = static::convertSpecifiers($format, $timestamp);
+		return static::_strftimeWithTimezone($convertedFormat, $timestamp, $date, $timezone);
 	}
 
 /**
@@ -1156,13 +1163,12 @@ class CakeTime {
  * Handles utf8_encoding the result of strftime when necessary.
  *
  * @param string $format Format string.
- * @param int $date Timestamp to format.
+ * @param int $timestamp Timestamp to format.
  * @return string formatted string with correct encoding.
  */
-	protected static function _strftime($format, $date) {
-		$format = strftime($format, $date);
+	protected static function _strftime($format, $timestamp) {
+		$format = strftime($format, $timestamp);
 		$encoding = Configure::read('App.encoding');
-
 		if (!empty($encoding) && $encoding === 'UTF-8') {
 			if (function_exists('mb_check_encoding')) {
 				$valid = mb_check_encoding($format, $encoding);
@@ -1176,4 +1182,29 @@ class CakeTime {
 		return $format;
 	}
 
+/**
+ * Multibyte wrapper for strftime.
+ *
+ * Adjusts the timezone when necessary before formatting the time.
+ *
+ * @param string $format Format string.
+ * @param int $timestamp Timestamp to format.
+ * @param int|string|DateTime $date Timestamp, strtotime() valid string or DateTime object.
+ * @param string|DateTimeZone $timezone Timezone string or DateTimeZone object.
+ * @return string Formatted date string with correct encoding.
+ */
+	protected static function _strftimeWithTimezone($format, $timestamp, $date, $timezone) {
+		$serverTimeZone = date_default_timezone_get();
+		if (
+			!empty($timezone) &&
+			$date instanceof DateTime &&
+			$date->getTimezone()->getName() != $serverTimeZone
+		) {
+			date_default_timezone_set($timezone);
+		}
+		$result = static::_strftime($format, $timestamp);
+		date_default_timezone_set($serverTimeZone);
+		return $result;
+	}
+
 }