How to change the default timezone being used for PHP DateTime Class

I just got done working on a project where the client wanted to display content on the site at 3pm Eastern Standard Time (EST) every day. While working on the query I realized that my server time was using UTC time so I needed to figure out a way to change to EST.

I was able to accomplish this using the PHP DateTime() Class. Take a look below:

	<?php
	// This will output current time in EST
	$timezone = 'EST';
	$timestamp = time();
	$datetime = new DateTime("now", new DateTimeZone($timezone)); //first argument "must" be a string
	$datetime->setTimestamp($timestamp); //adjust the object to correct timestamp
	echo '<b>Current Time: </b>' . $datetime->format('Ymd ga e');

	echo '<br />';

	// This will output current time + 24 hours in EST
	$timezone = 'EST';
	$timestamp = time()+86400;
	$datetime = new DateTime("now", new DateTimeZone($timezone)); //first argument "must" be a string
	$datetime->setTimestamp($timestamp); //adjust the object to correct timestamp
	echo '<b>+24 hours:</b> ' . $datetime->format('Ymd ga e');
	?>