Gareth Taylor's side host Chelsea on Sunday in a crunch clash, as the current holders and League Champions lock horns at the Academy Stadium.
With the London outfit having edged recent encounters, tests don't come much tougher but Weir says the benefit of being able to play at home in front of our own fans could prove pivotal.
"It's massive," she told mancity.com, "and for a number of reasons.
"Logistically, for us not to have to travel to London and having more time to recover - we've had players who have been all over the world - is good and of course, we'll have our fans there, supporting us at the Academy Stadium, which is exactly what we need.
"Last season, we played behind-closed-doors and we can see the difference, especially in tough moments, and I'm sure there'll be some of those on Sunday.
"But we know the fans are backing us all the way, like they have done all season, and we can't thank them enough for that.
"We know it will be a tough game and it will take us all performing to our best. I've played in a lot of City v Chelsea matches - league deciders, cup semi-finals - and it's always tough.
"We won't get many chances - both teams will have moments of possession and chances and it will be about who takes it on the day: who's clinical and who can survive under the pressure.
"We'll stick to our process and hopefully, come out on top.
"Hopefully, the fans will give us that extra push to see the game over the line. We're looking forward to seeing them on Sunday."
Sunday's semi-final clash is a 12:45pm kick-off at the Academy Stadium.
Tickets are available from just £1 for Under-16s and as the game falls on Hallowe'en, we have tonnes of activities and competitions planned to celebrate.
Secure your seat now and cheer us on to the Women's FA Cup Final!