The ITV1 serial will broadcast an hour-long live edition to tie in with its 40th anniversary celebrations next month.
As the special instalment will be shot entirely on location at the Emmerdale village, cast and crew must be prepared to cope with poor conditions on the night.
Speaking at an Emmerdale press conference, the episode's director Tony Prescott was asked whether there is a 'plan B' to keep the cast dry in the event of rain.
However, he replied: "No! It's so complicated to try and stage something of this magnitude. It's going to take us 11 days to rehearse it. We'd have to rehearse for another 11 days on top of that.
"You've got to make it so precise. There's no chance that we can move a camera on the night to another position, because there won't be a light there. Chances are, there won't be an actor there! So I think, to quote Danny Boyle, 'what is ours is going to be ours' on the night."
Meanwhile, series producer Stuart Blackburn joked: "An hour one October evening in a field on a hill in Yorkshire - what could possibly go wrong? It is thrilling and terrifying measure, I think. The village is my favourite character in the show. It's a spectacular and dramatic location."
He added: "If it does chuck it down, then Katie's wedding dress is just going to have to get sodden!"