PHP datetime format（）日期不正确

I have a PHP datetime object that I have been trying to convert into a string with DateTime::format() . But this keeps giving me a wrong date . For some reason I keep getting a date that is one day prior the day that I am running my code no matter what value I give the date. My DateTime object -

object(DateTime) {
   date => '2017-03-25 00:00:00'
   timezone_type => (int) 3
   timezone => 'UTC'
}

I use this to format the DateTime into a string -

$myDateObject->format('Y/m/d')

Gives me -

2017/03/23

There is absolutely no code between the line that prints the DateTime object and the line that formats the object ie there are no modifications made on the object .

If it helps the output of my server's date -u returns Fri Mar 24 06:08:39 UTC 2017 . Also if I create the date string with hours and minutes using $myDateObject->format('Y/m/d h:i') I get 2017/03/23 12:00

EDIT

The output of my date_default_timezone_get() is UTC

date('Y-m-d') gives 2017-03-24 ie today's date

Check out default time zone set in PHP
you may wanna try setting default time zone example: date_default_timezone_set('America/Toronto');