1. mid-March - the middle part of March. period, period of time, time period - an amount of time; "a time period of 30 years"; "hastened the period of time of his recovery"; "Picasso's blue period" Mar, March - the month following February and preceding April.

What is considered mid-March?

Any time in the middle of March.

What does mid-march late mean?

Yes it means near the end of March. ( As opposed to "early March" which would mean near the beginning of March)