This afternoon's game at Port Vale might have been postponed.
Referee Graham Horwood made a pitch inspection at 1.00pm as the area around the away goal was still frozen.
According to stewards, Horwood decided the match could go ahead as he was hopeful that the sun would shine on the frozen area before the game commenced - which it did. He also asked for the groundstaff to fork the area.
Whilst frost covers had been used, it still suggests that even when temperatures only drop to around -4C there is still a possibility of a postponement.