Temperatures were forecast to plunge as low as minus -4C and are not expected to rise much above freezing today.
An inspection is likely this morning, to avoid opponents Accrington Stanley making a wasted journey.
The sheeting was used on Monday night and taken off yesterday morning to allow the playing surface to breathe, but it was quickly relaid as the freezing weather continued.
Elsewhere it forced United’s under 18s to postpone their FA Youth Cup clash with Barnsley, which was due to be played at Thame United’s ASM Stadium last night.
The first team will be hoping the game goes ahead, as they look to bounce back from a disappointing display in Saturday’s 1-1 draw with Aldershot Town.
United and Stanley are well acquainted after meeting twice already this season, most recently drawing 3-3 in the original tie 11 days ago.
“There will be no surprises,” U’s boss Chris Wilder said.
“It’s a cup tie that gets finished on the night and we’re determined to make sure that we’re in the third round.
“(Hopefully) we can show a lot more quality than we did on Saturday, like we did up there in the second half, I thought we completely dominated it.
“But we understand they are dangerous and if you’re not right and don’t put teams to bed when you’re on top then the result can go either way.”
United will be without Simon Heslop, who starts a three-game ban after the Football Association rejected an appeal against his red card on Saturday.
The only new injury worry is Alfie Potter, who came off with a swollen ankle against Aldershot.
He is a doubt, but Wilder believes without swift action, the winger would have stood no chance of playing.
He said: “Alfie was limping, that was pretty obvious to see.
“He will be assessed, but what I would say, is if we hadn’t brought him off then he would definitely not be available.”
Accrington have a concern over James Beattie, who scored a wonder goal in the first cup tie.
The former Everton and Southampton striker pulled a hamstring in the warm-up to Sunday’s 1-0 defeat at Burton Albion, but may have recovered in time to play.
TONIGHT’S SQUADS Oxford Utd: from Clarke, Batt, Raynes, Wright, Capaldi, Potter, Chapman, Leven, Davis, Rigg, Constable, Craddock, Cox, Worley, O’Brien, Marsh, Brown, Boateng.
Accrington Stanley: from Rachubka, Winnard, Nsiala, Murphy, Liddle, Joyce, Miller, Lindfield, Boco, Molyneux, Amond, Beattie, Dawber, Clark, Eckersley, Barnett, Hatfield, Gray.