A Boston woman apparently froze to death while she was walking from the Financial District to her home in the North End while the city was experiencing brutally cold conditions early Saturday morning.Brian DiVasta said he was in Boston with his sister, Melanie DiVasta, at a comedy show Friday night. After the show, he said she went to meet up with friends in the Financial District and likely started heading home to her North End apartment after midnight."The expectation when we all left that evening was: 'You're going to take an Uber, right?' And I'm pretty confident that she took the Uber to meet up with her friends, and then she didn't (for the trip home). She decided to walk home," Brian DiVasta said.According to a Boston police report, Melanie DiVasta was found unresponsive shortly before 3:30 a.m. Saturday at Christopher Columbus Waterfront Park, where she was sitting on a bench.Melanie DiVasta, 47, was later pronounced dead. The park is less than 500 yards from where she lives."It's a walk that she's made more than a thousand times before, probably," Brian DiVasta said. "She was a Boston girl. She called the North End her home for more than 25 years. She loved her Dunkin' Donuts. She loved her country music. She loved her cat."An arctic air mass brought subzero temperatures and extremely bitter wind chills to Boston and all of New England from Friday night through Saturday morning.The National Weather Service said Boston reached minus 8 degrees Fahrenheit late Friday night, besting the previous Feb. 3 record of minus 5 degrees that was set in 1881.At about 5:15 a.m. Saturday, the temperature in the city had dipped to minus 10 degrees, smashing the previous Feb. 4 record of minus 2 that was set in 1886. In addition, the wind chill was about minus 35 degrees around that time."When you get this extreme cold, the margin for error shrinks," said Dr. Matt Mostofi, associate chief and vice chair for clinical affairs and quality for the Department of Emergency Medicine at Tufts Medical Center. "That can have profound consequences because when it's that cold, it doesn't take long to succumb."It is unclear how long Melanie DiVasta had been at the park. There is still police tape on the park bench where she was found."We will never see a colder night in Boston, ever, and it just happened to be that Friday night," said Chris Peters, Melanie DiVasta's brother."Probably any other night — literally, any other night in the last 25 years — it's no big deal. But it was just the wrong night. It was so incredibly cold," Brian DiVasta said.Melanie DiVasta was a graduate of North Reading High School and a memorial service will be held for her in North Reading this weekend.