How to get current date and time in WordPress?
You should use current_time function of WordPress instead of PHP date function for getting local date and time in WordPress. It will return correct value for you based on selected timezone in WordPress general options.
For me current_time('G') returns exactly 15 while PHP date('G') returns 10 which is not correct.
Hope it helps somebody since I didn't find related thread in the stackoverflow.
You can also install a plugin like Shortcode for Current Date to display the current time in your respective time zone. It also provides a great overview of various date and time formats.