Crowds gather for Chicago St. Patrick's Day parades

CHICAGO (WLS) -- This weekend's warm weather will likely mean a big turnout for this year's St. Patrick's Day festivities.

The traditional dyeing of the Chicago River began at 9:15 a.m. Saturday near Michigan Avenue and Wacker Drive.

Some science teachers from North Carolina used the river dyeing as a unique opportunity to teach their students about the chemicals used to change the water's color.

"We were just talking to some local people and they're like, 'Oh, if you're here this weekend, why not stop in for the parade and see what's going on,' and we were like, 'Heck yea! Might as well since we're all the way from North Carolina!" said Brad Rhew, an attendee.

"Just being a science teacher and the whole process, knowing that it's a secret recipe and that it is safe for the environment, it's a once in a lifetime experience," said Matthew Poston, an attendee.

Downtown, the St. Patrick's Day Parade stepped off at noon Saturday from Columbus and Balbo and travelling north to Wacker.

Attendees are encouraged to utilize public transit and get to the city's festivities early, as large crowds are expected.

WATCH: Chicago St. Patrick's Day Parade 2015

Some South Side streets will also be plenty busy when the reconstituted South Side Irish Parade kicks off Sunday on Western Avenue from 103rd south to 115th Street. Patrons of Country Fair Grocery, in the heart of Beverly, are stocking up on authentic Irish cuisine.

Owner Tom Baffes has over $30,000 in corned beef inventory and most of it is spoken for.

"Mrs. O'Brien came in this morning she bought 100 pounds, she said it is going to be so nice this weekend she knows there will be people she doesn't even know coming over to her house to visit," Baffes said.

The brisk business in brisket translated to other Irish items.

"The cabbage, the corned beef, the baby carrots, you got the Winston's Irish soda bread," Baffes said.

"It is amazing, it is huge, I am actually from Ireland so it is very important to us, we keep our heritage going," said Ann Marie Killeen, a customer.

In a neighborhood where celebrating that heritage had to be suspended for two years due to concerns over public alcohol consumption, the return to what St. Patrick's Day is all about is welcome.

"On St. Patrick's Day in Ireland you don't dye the river green, you go to church, you go for a quiet drink and you wear the shamrock on your lapel, on your suit, it's a church-going day," said Liam Hawkshaw, a customer.

"There's a twinkle in our eye and a song in our heart and everybody, just for a moment at the parade for those two hours, just relax and have fun with their kids," said Tom McCorty, chairman of the South Side Irish Parade.