This page of the guide to Spider-Man Miles Morales contains information about one of the characters in the game - Hailey, from whom you will receive the Winter Suit.
Hailey is one of the residents of Harlem. You can meet her already at the beginning of the game. When Miles leaves the subway station, he finds Hailey working on a new Spider-Man mural.
The girl also appears many times during the main missions - you will meet her e.g. on the streets of Harlem during the Time to Rally mission. After completing the side mission Harlem FEAST Shutdown you will get access to the next mission - We've Got the Lead!.
Then go to the park in Harlem to talk to Hailey - a marker on the screen will lead you to her. After completing the mission, return to her to get the Winter Suit.