Friday's meeting at Sandown is subject to an inspection at 8am.
Temperatures of zero degrees were reported overnight but that is forecast to drop with an increased wind chill and the possibility of snow flurries early on raceday morning.
Clerk of the course Andrew Cooper said: "We covered the entire course on Wednesday and we're OK at the moment, but it's hard to predict with any great degree of certainty what will happen."
He continued: "It wasn't as low as it might have been last night but this weather, with wind chill and winds, is set in now for the next few days.
"It could be colder tonight with suggestions of minus 2C and the possibility of snow flurries on Friday itself.
"Under the covers we should be fine but when you add in a minus 3C or 4C wind chill that does have an impact on the ground, there's no doubt about it, and that's the added complication.
"We're left with no choice but to inspect and see what the weather does."
13 May 2013
Fabre confirms Ocovango for EpsomAspect on route to big things
Room at the top for Cityscape
Freedom steps into chasing ranks
Lucky thirteen in line for Lockinge
Galway beckons for Swinton hero
Sajjhaa set for late return
Cadeaux thriving in Singapore
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Liber takes aim at Musidora
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Duntle back to winning ways
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12 May 2013
No hurry for Jammy plansGuest in hunt for more Ascot glory
Vow set for Goodwood return
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Buick aiming for French strike
Angel flies home to land Chartwell
Barizan bounces back in style
Queally lights up Ascot meeting
Ektihaam storms to Buckhounds win
Nevis takes depleted Trial contest
Hard-fought battle won at Haydock
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Ascot drama for Fanning
11 May 2013
Felix foot-perfect on fencing debutCavalryman leads Cup charge
Ramsa ready to stand Trial
Duntle out to dazzle in Amethyst
Swift return doesn't bother Moran
Garman gives Bolger hope
Henderson: Ground vital for Voice
McMahon sweet on Tart Ascot claims
Murphy to move to France
Athos flies to Ormonde glory
Dee day for impressive Magician
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Marengo ready to do battle
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Barizan sneaks into Swinton
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10 May 2013
Telescope focus is on DanteBlinkers considered for Guarantee#
Bonfire camp bemoan Huxley flop
Moohaajim has six appeal
Ascot welcomes a couple of Guests