How can PHP developers ensure that date formatting functions work correctly across different server configurations and time zones?

PHP developers can ensure that date formatting functions work correctly across different server configurations and time zones by setting the default time zone in their PHP script using the `date_default_timezone_set()` function. By explicitly setting the time zone, developers can ensure consistent date and time calculations regardless of the server's configuration.

// Set the default time zone to UTC
date_default_timezone_set('UTC');

// Use date formatting functions with confidence
echo date('Y-m-d H:i:s');