The National Hunt fixtures at Sedgefield and Market Rasen on Tuesday must pass course inspections on raceday morning.
Sedgefield will stage a precautionary inspection at 8am "due to the forecast of low overnight temperatures and possible wintry showers".
Officials at Market Rasen have called a 9am precautionary inspection as overnight temperatures could dip to as low as minus 2C.
Snow and sleet showers are also expected tomorrow morning.
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