Yes, winter pumps are possible. Sometimes this is more costly due to snow or ice coverage and trying to reach your septic system.
When homes or cabins are unoccupied for long weekends or extended periods of time septic system cannot maintain sufficient temperatures to avoid freezing. Frequent use, warmer water temperatures, and greater water use overall are important in cold temperature stress situations.
Beware of little leaks like a toilet or shower head leak. These small trickles freeze easy within the pipes and can cause the pipe to freeze solid.