As Natick’s new $78.5 million high school nears completion this summer after nearly two years of construction, town and school officials are ringing in the new by saying goodbye to the old.

With just weeks to go before the current Natick High School is razed to make way for a parking lot and playing fields beside the new building, those who hold the school and its legacy near and dear can take part in a full day of activities Saturday to commemorate memories made in the 58-year-old building.

There will be kids’ activities from 10 a.m. to 3 p.m. at the town’s Memorial and Mahan fields, including track, basketball, soccer and baseball events, obstacle courses and games, face-painting, and mini-manicures.

JOHN BOHN/Globe Staff

Doug Flutie graduated from Natick High School.

At the old high school, there will be building tours as well as music and speeches, a drama presentation, sports contests, and photo opportunities.

A final pep rally is scheduled for 2 p.m., and Natick High memorabilia will be available for purchase throughout the day.

“Everything you can imagine the school has accumulated in 58 years will be all for sale,” said event organizer Judy D’Antonio, adding that the proceeds will fund a to-be-determined need at the new facility.

Organizers have also arranged an evening gala, for ages 21 and older, in the old school building, with the ticketed event to be emceed by local TV celebrity Susan Wornick, a Natick native. The gathering, from 7 to 11 p.m. Saturday, will include a DJ and dancing, a cash bar, class reunions, and a meet-and-greet with Natick notables, including police officers and firefighters, nominees for Natick High’s Wall of Achievement and Hall of Fame, and famed football brothers Darren and Doug Flutie.

Organizers expect several thousand people to attend the daytime activities, and about 1,000 people at the evening gala, said D’Antonio, who organized the event with Parent Teacher Student Organization copresident Jane Boyle and Natick High graduate Terri Flutie.

D’Antonio said Natick graduates will travel from around the country to revisit their high school’s halls and revel in nostalgia.

“Those were happy days,” D’Antonio said. “Most of them are off in the work world, making a living, raising a family, and trying to make their way in the world. High school was a carefree time, and they want to remember not only their former friends, but their teachers and support staff. They’re looking to reconnect with all of them and reminisce.”

Yet as Natick High alumni prepare to celebrate the old building’s life Saturday, more recent graduates were willing to point out some of the school’s drawbacks while still cherishing its legacy.

During the high school’s commencement ceremony two weeks ago, senior class president Benjamin Collins took note of the end of an era, with the nearly 300-member class of 2012 the last to graduate from the old building.

Chuck Stoody/AP File

Darren Flutie also graduated from Natick High School.

“We are the last without heat in the winter, we are the last to perform on that stage, we are the last of the Red and Blue, and the last to love old Natick High,” Collins said, adding that seniors kept mum when it came to complaining about their school’s failing physical condition.

And while the move to the new high facility arouses nostalgia among students, teachers and faculty, Natick High principal Rose Bertucci — who has worked in the school for for 27 years — said the change is long overdue.

“It’s always difficult to transition when you’ve been in one place for so long, but to say that we need a new building is to say it lightly,” Bertucci said. “We have barrels everywhere catching water, the heating system is hanging on by a thread, and the building is just old and tired.”

Bertucci lauded town officials and voters for approving the new building, which is slated to open for classes in late August.

“When you walk into the new building, your jaw just drops,” Bertucci said. “The teachers deserve to be in a professional place, and the students deserve a great place to learn.”

With this winter’s weather proving to be a contractor’s dream, construction on the high school has remained on or ahead of schedule.

The new facility will feature technological advances, such as classrooms equipped with overhead projectors, Wi-Fi available throughout the building, and 1,200-square-foot science labs equipped for courses in robotics and website design.

It also features an auditorium that seats 800 people; a separate 97-seat lecture hall; a TV studio and production room; an 18,000-square-foot gymnasium with modern exercise equipment and a 6,000-square-foot track that will be made available to the public; and the addition of a preschool program spanning six classrooms.

The town is also taking steps to make the building energy efficient and green, including installing a gray-water system that will collect rainwater runoff from the roof for irrigation and other uses, solar panels to power at least 5 percent of the school’s energy needs, and HVAC systems that automatically detect the number of occupants and adjust the climate accordingly.

While the list of improvements sounds enticing, some students have mixed feelings about moving to a new building.

Class of 2014 president Marie Libbin said she would appreciate the upgrades, as the old school proved problematic for learning.

“Often, it was either really hot or really cold, so you’d be taking a sweat shirt on or off over and over,” Libbin said. “There were constant leaks in the hallways, and if it rained, we would get rained on too, even though we were inside.”

Libbin, an enthusiastic thespian, said she also looks forward to the new auditorium, where school plays and musicals can seat more audience members.

Still, Libbin said parts of the old high school will be missed.

“This high school has been here so long, and most of us who have grown up in Natick are used to being here,” Libbin said. “Some of us have parents and grandparents who have gone here, and it’s cool to see that legacy.”

Libbin said she feels nervous that the upperclassmen — seen as leaders to incoming freshmen — will be navigating through new hallways and classrooms as well, potentially becoming lost like the newest students.

“It will be sad at first, because going into junior year, you’re supposed to have the whole school down,” Libbin said. “I think overall it will take time to adjust, but I think it will be an awesome change in the end.”

Tickets to the evening gala cost $40, and will be on sale at Jones Drug, Debsan Wallpaper and Paint Co., Casey’s Diner, Fair & Yeager Insurance Agency, and the town’s schools.