The weather outside was frightful, but the folks inside delightful

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.

``We sent letters to 10 Soviet mayors with offers to set up a sister city relationship,'' explained Jeb Brugmann, president of the association. ``The first reply came from the capital of Armenia.''

Cantabrigians are quite fortunate that Yerevan answered first. It is one of the most beautiful cities of the Soviet Union, with a history that goes back to antiquity. It is nestled in Ararat Valley, with the great peak of Transcaucasia towering above - Mt. Ararat. The people of Yerevan love their city fanatically and welcome company.

I must warn you that it's possible to become a ``victim'' of their hospitality. Yerevanians are ready, 24 hours a day, to show you the sights and treat you to gastronomic masterpieces.

Apparently the first group from Cambridge did not avoid that fate. Last August, 15 people, led by Ellen Mass and Madelyn Holmes, visited Yerevan. They were greeted by Mayor Edvard Avanyan and had in-depth meetings with people at Yerevan State University and the Writers' Union. They had a full and rewarding day at an English-language elementary school. And, of course, they got to know the ancient Armenian heritage through tours and home visits.

Last October, Suzanne Ehly and Hayg Boyadjian, two exchange committee members, led a successful and significant Musicians Exchange to the Soviet Union. The group consisted of 15 classical, jazz, and gospel musicians, plus a photographer, all from the Cambridge area. Some of the musicians taught master classes at the Komitas Conservatory and workshops at the schools. There were several faculty-student round-table discussions and many impromptu jam sessions and formal concerts. The musicians were enthusiastically received wherever they went.

``I have traveled all over the world and studied in Europe,'' continued Mr. Brugmann. ``I've often encountered anti-American feeling and heard people talk about `ugly Americans.' But in the Soviet Union, the reception has been only warm. Last May, a Soviet delegation headed by the mayor of Yerevan came to Cambridge. Eight hundred people came to a dinner in their honor. Some musicians from the delegations gave a concert at Sanders Theatre at Harvard University, which 1,200 people attended. Our guests visited a church in an Armenian area, where 700 people greeted them.

``But don't think everybody in Cambridge was glad to have the Soviet visitors - like the police who were supposed to guard them,'' said Brugmann. ``They weren't too happy with the idea of joining in `brotherly ties' with a communist city. But after a week, they had already exchanged addresses with the guests, invited each other home, given the Yerevanians official Cambridge Police emblems.''

Chatting with the members of the association that snowy evening, it occurred to me that these are the kind of people who can form the basis of good relations between our countries. No declarations about friendship or mutual understanding can replace live contact - the kind of contact that made reserved and mistrustful Cambridge policemen interested and warm.

Sister cities are a fine idea. But there's one problem: What are we going to do when all our famous cities are paired off?

Well, I guess we'll have to start pairing off families.

Yelena Hanga works for the Soviet weekly Moscow News. One of two reporters who were in the US on a journalism exchange arranged by the New England Society of Newspaper Editors, she worked at the Christian Science Monitor.