You can change the timezone for your account or for a specific folder by adding this rule to your .htaccess file:

SetEnv TZ Timezone

For example, if you wish to change the timezone to America/New_York, you should add this line to your .htaccess file:

SetEnv TZ America/New_York

This way your scripts will use your local time instead of the server time.

A full list of the available timezones can be found at this URL.