Tuesday's jumps fixture at Newcastle must pass a course inspection at 8am on Monday.
The going is currently soft, but the track is covered in snow.
Exeter's meeting is subject to a precautionary inspection at the same time.
A statement issued by the track said that a thaw had started on Saturday, but there is still snow on the track.
The course is also frozen in places,with "some waterlogging".
The statement read: "Temperatures are now 7C and should not drop below 2C tonight so by morning most of the snow should have gone and we can take a look at 8am to asses our chances of racing Tuesday."
Monday's National Hunt meeting at Lingfield is subject to a further inspection at 7.30am on raceday morning.
Clerk of the course George Hill called an initial inspection for 8am on Sunday and is optimistic enough to announce a second check for Monday morning.
Hill said on Sunday morning: "There's been a big improvement in the last 24 hours, but we do need it to improve again.
"We're going to start moving a rail this morning as some areas aren't too bad and other areas are a fair bit worse and fairly solid. We're going to try and get creative.
"We had three millimetres of rain on Saturday, which helped. If we get a few more showers today that would be good, although we don't want too much rain as the ground is already heavy.
"Temperatures could get up to 8C today, so we'll just have to hope it improves enough."
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