RFU Regulation 6 - Suitability of the Pitch or Weather conditions (6.20/21)
Issue of pitch suitability in various conditions and with various scenarios outlined in the attached
https://www.englandrugby.com/dxdam/65/656ceb07-0363-47e3-b247-34f99e49ee28/Regulation%206.pdf
Note links often move on 3rd party sites. If it has then just google RFU Regulation 6...?
Attached is further info to help you make and manage the right decision.