Mountain Rescue teams, an RAF Sea King helicopter, police and volunteers have been involved in the search for Dennis Brough and Robert Shaw over the last two days.
Search teams are concerned for the two men after heavy rain, sleet and snow fell and temperatures plunged to -7 degrees overnight.
Mr Brough, 66, disappeared from his home at Stranraer on Wednesday. Mr Shaw, 52, from Crossmichael, near Castle Douglas, has not been seen since Friday.
The RAF Sea King from HMS Gannet joined police searching for Mr Brough, who was last seen by his neighbour leaving his home in Garrick Drive.He was driving his black Land Rover Freelander. He is described as white, 6ft and of slim build. He has grey hair and either a grey beard or grey “goatee”. It is not known what he was wearing when he left his house.
Freezing conditions, heavy rain and low cloud have been hampering operations.
The Galloway Hills Mountain rescue team joined a police search for Mr Shaw, who has been missing from his home since Friday. Despite two days of searches by police, friends and volunteers there have been no sightings of him.