A suicide bombing at an Ariana Grande concert at Manchester Arena killed 22 people and injured 116.
Organisers said the Games, an open and free event for the public, will take place on Friday as planned.
"I think it's really important that it does go on," Peake, who was raised in nearby Chester, told BBC Wales Sport.
"We [athletes] were asking the question if it was going ahead. I'm really glad that it is and I really hope the city pulls together and there's a great atmosphere, which I feel there will be.
"Pride is one of the words, the whole city is pulling together.
"Pole vault suddenly seems insignificant when things like that happen in life, but at the same time it's really great to be able to step up and get that community spirit in Manchester."
The women's pole vault will be the first event of Friday's Great City Games, with British Olympian Holly Bradshaw among those competing.
Peake, who won a silver medal for Wales at the 2014 Commonwealth Games, has spent much of her life in Manchester and taken part in the event in previous years.
"I grew up around that area. I know the area very well and I've been to the MEN [Manchester Arena, where the explosion happened] to see concerts myself," the 33-year-old added.
"It's very close to home. It will have extra special meaning jumping there.
"There are going to be extra security measures, so hopefully everything goes well."
Wales pole vaulter Sally Peake says athletes will be "proud" to compete at Manchester's Great City Games following the attack in the city on Monday.