Voter turnout was termed "moderate" yesterday by Cambridge Election Commission officials as one of the city's duller biennial campaigns and the winter's first bitter cold combined to dampen interest in the election.

At the polls voters had to choose from among 34 candidates for nine seats on the City Council. They found 25 hopefuls vying for their favor for the six School Committee positions.

Earlier in the week, Francis P. Burns, executive secretary of the Election Commission, said that he expected about half of the city's 48,000 registered voters to appear at the polls, down considerably from the 67 per cent that voted in the 1971 municipal election.

Election officials were reluctant yesterday to estimate voter participation in particular neighborhoods. "I wouldn't be honest if I tried to make an estimate before the official figures are in," Constance Milton. one of the City's four election commissioners, said.

All candidates run at large for both the City Council and School Committee, but most rely on strong bases in particular neighborhoods. Thus, the turnout of voters in one neighborhood relative to another plays a crucial role in the outcome.

Strong turnouts in the Harvard area and western parts of the City should favor the liberal CCA and GRO slates, while the majority of voters in East Cambridge and North Cambridge are expected to cast their votes for candidates on the more conservative Independent slate.

The drama commonly associated with election night--the impatient wait for the first spatterings of early returns, predictions based on early precincts, subdued concession statements, and victory speeches to hordes of cheering supporters--is unknown in Cambridge.

Preliminary results will not be known until Friday, due to the involved ballot-counting process under Proportional Representation, Cambridge's unique and controversial system of voting.

In spite of the heavy competition most incumbents are expected to win reelection easily. Only four seats appear contestable. The council seats of Robert Moncreiff, who is retiring from the council this year, and Henry F. Owens II, a black councillor who has lost most of his white liberal support over the past two years, will be up for grabs. On the School Committee, two incumbents, Donald A. Fantini and David Wylie, have decided to try their luck in the council race so newcomers will fill their seats.

The vote counting begins this morning at 8 a.m. at the Longfellow Elementary School. Over 100 election workers will be sworn in and instructed how to tally the ballots.

Milton said the workers will complete the first unofficial count today, categorizing the ballots by ward and candidate.

After that, the election workers review each ballot for irregularities. Two years ago, nearly 700 ballots were declared invalid because voters did not mark them properly. For instance, if a voter marks an "x" or more than a single "1" on his ballot rather than enumerating his choices in order, his ballot is invalid under the PR system.

The number of valid ballots is then totaled and the quota of first place votes necessary for election is calculated as a percentage of this number.

When a candidate reaches the quota, a percentage of his surplus "2" ballots are redistributed to the "2" candidates on each ballot.

Milton said the official count would begin late in the week and continue from 8:30 a.m. to 5 p.m. daily until nine candidates have passed the quota for City Council and six for School Committee.

Candidates and their supporters are permitted to observe the counting process from a distance