Saints won seven of their eight matches during the month to leave them on the verge of clinching promotion back to the Championship.
Adkins beat Sheffield Wednesday boss Gary Megson, Exeter's Paul Tisdale and Lee Clark at Huddersfield to the award.
Judging panel member Alan Curbishley said: "Nigel has done a great job since his appointment and his side have all-but secured promotion."
Source: PA
Source: PA