You need to look at each college’s requirements. If using the common app here are the directions (college self-apps and/or coalition app may have different guidance):
To meet an application deadline, you must submit your application materials by 11:59 pm on the deadline date posted on your Dashboard. The end of the deadline date is in your local time zone, not the college’s time zone. Keep in mind, all timestamps are recorded in EST (US Eastern Standard Time).
It is always better to submit well before 11:59 pm to avoid last minute issues with your computer or internet access that might cause you to miss the deadline!
Example 1:
You are in New York and have an application with a deadline of January 1. You have until 11:59 pm Eastern Standard Time January 1 to submit your application.
Example 2:
You are in California and have an application with a deadline of January 1. You have until 11:59 pm Pacific Standard Time January 1 to submit your application.
Example 3:
You are in Shanghai and have an application with a deadline of January 2. You have until 11:59 pm China Standard Time January 2 to submit your application.