The 22-year-old has joined after Sandgrounders defender Chris Doyle was ruled out with a long-term knee injury.
Howe came through the youth system at Scunthorpe but he failed to make an appearance at the Iron and moved to Lincoln in 2015.
He is available for the game against Tranmere on Saturday.
Find all the latest football transfers on our dedicated page.
Southport have signed defender Callum Howe on a one-month loan deal from fellow National League side Lincoln City.