Taunton's richest ever meeting on Saturday could be the best chance of any turf racing going ahead over the next few days.
Temperatures in Somerset are fairly tropical compared to most of the rest of the country, but even they are not completely safe, with a band of either snow or rain moving in.
"Whether we get rain or snow we'll just have to see as it depends on which forecast you read," Taunton groundsman Kevin Council said.
"It is due to hit us early on Friday so we should know by 10am where we stand.
"At the minute we are perfectly raceable and the temperatures are not causing much concern.
"It's our biggest raceday so we'd love it to be on."
Ascot's meeting, which features Sprinter Sacre's return in the Grade One Victor Chandler Chase, will need to survive a 4.30pm inspection on Friday, but snow is forecast.
"There are some signs of frost under the covers," clerk of the course Chris Stickels said.
"I'm pretty confident we could race (on Thursday) but could not be certain unless I lifted the covers right off.
"It is due to remain cold, although maybe not minus 4C again.
"Snow is forecast for Friday afternoon and evening, so it makes sense to have a precautionary look on Friday when we'll have a good look under the covers and we'll be able to assess the snow situation."
Haydock's meeting on Saturday, which is due to stage the Peter Marsh Chase and a Champion Hurdle Trial, is in grave doubt.
Friday's meeting at Musselburgh was abandoned on Thursday morning, while Chepstow's fixture on the same day must now pass an inspection at 8am.
Lingfield's all-weather meeting on Friday is also subject to an 8am precautionary inspection on raceday morning due to the threat of snow.
Towcester's meeting on Sunday has already been abandoned.