THE day was so cold and snowy that even I - a native of Moscow - was concerned. Stores closed early. Occasional pedestrians hurried home. Life in the city ground to a halt. I had been invited that evening in January to a special gathering of the Cambridge-Yerevan Sister City Organization, and I was sure no one would venture out of their warm houses for the meeting. To my surprise, the hall was full. People set up chairs, arranged appetizing pastries on a table, made coffee, hung up pictures of the sights of Yerevan. It wasn't much warmer inside than out, but that didn't cool people's enthusiasm.
There are 17 pairs of Soviet-American sister cities. The Cambridge association, formed five years ago, is made up of scientists and students, librarians and taxi drivers, businessmen and musicians. Among them is Cambridge Mayor Alfred Vellucci.
``I have been elected four times, and each time I have linked Cambridge with a foreign city - in Italy, Portugal, Japan, and now the USSR,'' Mayor Vellucci said.
``It's bad when people from different countries don't have the chance to meet face to face. When this is the case, the press takes on the role of communicator. Our journalists declare that we're right and the Soviets are wrong. The Soviet media do the same thing. We can avoid that only through direct contacts between cities.
``The time has come to throw open the doors of communication so the winds of cold war can blow out. I dream of the day when someone from Cambridge can buy a plane ticket and go see friends in Yerevan, and someone from Leningrad can come as a tourist to Boston. I think things are heading in that direction.''
The residents of Cambridge decided to find a sister city in the Soviet Union in 1983. City Hall sponsored a public hearing, where people could offer suggestions. The choice was narrowed to 10 cities.