The surface at the Bird’s Nest stadium in Beijing was described as “bad” by United boss Jose Mourinho on Sunday.
And before the game was called off, City boss Pep Guardiola said his main hope was for players to avoid injury.
Both City and United said “tournament organisers and clubs” decided to cancel the match at the 2008 Olympic Stadium.
Rain had fallen overnight and there were forecasts of more heavy rain on Monday.
The clubs’ planned training sessions were switched away from the stadium on Sunday to the Olympic Sports Centre, about a mile away.
The fixture cancellation capped a chaotic 24 hours for the Red Devils. Manager Mourinho’s planned news conference had to be scrapped as too many people tried to get into a room which was deemed too small and too hot.
And a plane carrying some of the players had to make an unscheduled stop in Tianjin, around 160km from Beijing, as storms hit the Chinese capital.
United will leave Beijing to return to Manchester later on Monday as planned, while City are due to fly to Shenzhen on Tuesday for Thursday’s game against Borussia Dortmund.