On a snowy day last winter, an irate parent called Montgomery County School Superintendent Edward Andrews to find out why the public schools were closed for a snow day.

Andrews had arrived, as usual, at 7:30 a.m., and was immersed in the exhausting work of school closings when the phone rang.

"I'd like to speak to the jackass who closed the schools today," the caller said angrily, unaware that the superintendent himself had answered the phone.

"Jackass speaking!" Andrews confessed gleefully.

This is the sort of lore, passed along by teachers and principals, that Andrews will leave behind if he retires as announced next June. Superintendent of the 92,000-pupil school system for the past three years, he is known for humor, self-effacement, and even-tempered cool.

Andrews, more than anyone else involved in the controversial countywide school closings of the past two years, has survived thus far with grace and diplomacy. He escaped the bitter attacks of community activists and, perhaps more astonishingly, has managed to please the seven-member school board at the same time.

Beneath the easygoing exterior is a man who mastered the art of political survival. At the same time, Andrews is known for being laid-back and scrupulously honest. He is also cautious and, above all, diplomatic.

His announcement last week that he plans to retire from the $70,000-a-year post was a vintage Andrews performance. At a press conference several hours after the story broke in The Washington Post, he convincingly dispelled notions that philosophical differences with the controversial board majority were a factor in his decision to resign, and suggested that news reports alleging this were inaccurate.

Andrews refused earlier to comment for the record. As the consummate diplomat, he has been careful not to repeat in public some of the statements he has made in private to his closest associates. He said during his news conference that he had never talked to any reporter about his decision to resign.

Under the glaring eye of board conservatives, who were on hand for his official announcement (conservative leader Marian Greenblatt brought a tape recorder to the event), Andrews remained jovial and in control.

"Somebody must have died," were his first words as he gazed out at a phalanx of reporters and board members who greeted him in stony silence.

Then he calmly explained that the fatigue of his 70-hour work week had become too much of a burden, that he had resisted taking the job in the first place, and had said at the outset he might retire before the term expired in 1984. He wanted more "leisure time," he said, and he vowed not to have a public role in the general election on Nov. 2.

The inevitable questions about differences with the board majority came and went, with Andrews hardly batting an eye. By the end of the press conference, ruffled feathers on the school board had been smoothed, with the conservatives happily persuaded that Andrews' resignation would not be used as a campaign issue against them.

Board president Eleanor Zappone quickly branded as "totally erroneous" a Post article that reported that Andrews was disgruntled in part because of his fundamental philosophical disagreements with the conservatives' policies on racial integration. (Andrews said as much in the press conference, but added that this was not the determining factor in his resignation.) Greenblatt said the Post story was "utter fabrication."

It is no secret that he had fundamental philosophical differences with the board on some key racial integration issues, most notably the board's school closing plans that were overruled by the State Board of Education. And he had a large workload that was exacerbated, in part, by the county board's handling of the closing cases.

Finally, he is a man who by nature is a peacemaker, who dislikes being in the public spotlight and who shuns controversy. As superintendent of a school system embroiled in one of its most bitter periods, Andrews was hardly in a comfortable or enviable position.

Andrews was not implicated in the school board's controversies. He managed to keep all sides relatively happy during a stormy time. As his closest associates have stated, it would be hard to believe that fatigue and long hours were the only reasons Andrews would be leaving.