When does the second semester start?

The start date of the second semester varies greatly depending on the educational institution (school, college, university) and the country. There's no single answer. To find out when the second semester starts, you need to specify:

* The specific school or university: The school's website will have the most accurate academic calendar.

* The country: Academic calendars differ significantly between countries.

* The level of education: High school, undergraduate, graduate, etc., all have different schedules.

Please provide more details so I can help you find the correct information.