In November 1971, it was frost on more than pumpkins when Indian Prime Minister Indira Gandhi arrived at the White House as Richard Nixon's guest. When she heard him tell of 5,000 made homeless by a cyclone in India's northwest state of Orissa, aides remember that she icily countered with comments about millions of East Pakistanis seeking refuge in India because of a man-made calamity--war.

Thursday night, instead of frost it will be music in the air--at least, after President and Mrs. Reagan's dinner for Gandhi. Maestro Zubin Mehta will conduct 60 members of the New York Philharmonic Orchestra in a concert under the stars on the South Lawn if it's clear and under a tent in the Rose Garden if it rains.

House Foreign Affairs committee member Rep. Jonathan B. Bingham (D-N.Y.) and his wife June, traveling in India last month, were surprised one day to learn that Prime Minister Gandhi had asked to see them. Obviously more interested in finding out what the mood of the U.S. Congress would be when she reached Washington this week than in dwelling upon her own, Gandhi was polite but spare in her responses during the interview. "The Nehrus are great at letting the tennis ball fall in their court," says a wry June Bingham, remembering a long-ago interview she and her husband had with Gandhi's father, Jawaharlal Nehru.

Gandhi made it clear that she wanted to be friends with the United States after more than a decade of strained relations over what India has perceived as America's partiality toward Pakistan. But not until the congressional wife began questioning her about equality of the sexes in India did Gandhi start to loosen up, said June Bingham.

In the United States, Bingham told her, the great unresolved question continues to be which comes first, careers or babies. "It was like taking the cork out of a champagne bottle," Bingham, a free-lance writer, recalls. Not only did Gandhi go on at length about the prominent role Indian women played in politics both before and after independence but also about how she had handled motherhood and career. "Even when her children were in school, she said she made it a point to be home when they were," says Bingham.

Despite Indian laws that ensure equality of the sexes, Gandhi said there remains a residual anti-woman prejudice. "If a man has 10 daughters," she told the Binghams and U.S. Ambassador to India Harry Barnes, "he will still try for a son."