Sunday's meetings at Exeter and Hereford and Monday's at Catterick all face inspections before they can be given the go-ahead.
Exeter, which is raceable at present, will stage a precautionary 8am inspection on raceday due to the threat of frost as sub-zero temperatures are forecast for the next two nights.
Hereford are checking at 11.30am on Saturday following rain and a mild night in an attempt to give the fixture every chance, although the forecast is not favourable.
Exeter clerk of the course Barry Johnson said: "We had no frost on Thursday night and we had rain rather than snow. We've called a precautionary inspection to keep everyone ahead of the game.
"It could be minus 4C on Friday and Saturday night, but the daytime temperatures give us a chance. It depends how quick the temperature rises."
At Hereford, clerk of the course Keith Ottesen said: "It didn't drop below zero all night and we had rain, not snow, which helped shift most of the frozen areas, although there are still a few frozen patches.
"It could be a false dawn as it is supposed to be very cold on Friday night, but we couldn't call it off now. It rests on how cold it gets tonight really."
Officials at Catterick will stage an inspection at 8am on Sunday to assess the prospects for Monday's meeting. The North Yorkshire circuit remains frozen and partially covered in snow, leaving clerk of the course Fiona Needham less than optimistic.
"The course has been frozen since February 3 and the ground is frozen solid at the moment. The only glimmer of hope is that it is due to get warmer from Sunday into Monday, but I fear it might be too little too late," she said.
"We'll review the forecast on Sunday morning and see if there is any point carrying on, but I'm not very hopeful of racing at this stage."
