[Alan]

Season dates:

McMurdo: regular Summer season starts about late September or early October, and goes until late February or early March. However, there may be a late flight in late March, and WINFLY, the first flight to prepare for the summer season, is in late August or September. McMurdo can handle an emergency flight most of the year, but there just isn't a reason for many flights during the winter.

South Pole: Summer begins late October or early November. Last scheduled flight is 15 February.

I don't know the dates for Palmer, which is reached by ship in any case.