One memory of Latin America that Rosalynn Carter will surely take home from her two week tour of seven countries is that of rain.

Expect for the time she has spent here, Mrs. Carter has been rained on daily. When she arrived Monday at her first stop - Kingston, Jamaica - a heavy shower had just stopped, and as she gave her airport address a fine drizzle sifted down on her.

That night it rained so hard that Prime Minister Michael Manley could not have the outdoor buffet he had planned in her honor. At the last minute, he disnvited 205 of the 250 guests and instead had 45 persons for dinner inside.

The next morning Mrs. Carter had to cancel a visit to sugar cooperative because it was flooded. She had planned to go into the fields and cut cane with the workers.

A U.S. official traveling with her said she was quite disappointed about the cancellation.

"She really wanted to do this one because she wants to do thing that aren't just the traditional lady's stuff," the official said.

In San Jose, Costa Rica, as Mrs. Carter swore in 16 Peace Corps volunteers during a garden ceremony at the U.S. ammbassdor's residence, large raindrops spattered the guests.

And Quito, Ecuador, as she held a new conference on a platform outside the residence of U.S. deputy chief of mission, it rained again. The drops were washing away my notes, and struck by the absurdity of it all, I looked up at Rosalynn Carter and started laughing. She started laughing too.

The First Lady remembers the gaffes, and she told this one about her visit to the head of the Supreme Court of Ecuador, the courtly and distinguished Luis Jaramillo:

"There were photographers all out in the front and I shook hands with the head of the Supreme Court, and then we started to sit down in the chair. The chairs were low, and he leaned over this way, and I leaned - and we just cracked our heads.

"I could see it being a picture on the front page of the paper. But he never mentioned it. We just sat down like it had not even happened."

At the Jamaica airport Mrs. Carter could not be heard over the public address system. The problem was that "the White House sent down a 'mult Box," but they didn't send anyone who knew how to operateit," said a disgusted local U.S. official.

A "mult box," or multipexer, is a stel suitcase with a lot of sockets which, when properly hooked up, can feed sound to broadcast or public address systems. The mult box problem occurred again at the Quito airport. As a result, Rosalynn Carter, who has a low, soft voice and who speaks rapidly, was heard by almost no one.

For most of last week we were spending only one night in each country. By the time the first lady reached Quito, the effects of fatigue, as well as the 9,300-foot altitude, were setting in.

hat night she went to dinner at the home of Edwin Corr, chief of mission. She said that he and others told her and her staff "that if we were tired, if we would sniff a little oxygen. It would make us feel better and that they had it in the cars and they had it in the house and they had it everywhere. So I had about three breaths of oxygen - like that - and it did. It picks you up. But that's the only time I've had anything."

The final results will not be in until the trips ends this week, but by most account Rosalynn Carter is wowing them in Latin America so far. CostaRica's president, Daniel Oduber, told some reporters the other night, in what could be a slight exaggeration, that her visit "is important because for us it's exactly the same as if President Carter had arrived and made a personal contact."

Warning to the subject, he said. "We feel immediately at home with her. She's very natural and she goes directly to the point. She's well informed. She knows exactly what they (The United States) can do and what they cannot do, which is most important."

At first Mrs. Carter was not all that sure of herself. In her first session with Jamaica's Prime Minster Manley, he asked what was going on at the Paris meeting of industrailized and developing nations. She didn't know.

But by the end of the week she was happily volleying - at least with the press - such issues as F-4E fighters, Israeli Kfir jet sales and the Ayacucho declaration against an arms race in Latin America.

If some dipomats - the Ecuadorians, for example - were reluctant to bring up a touchy subject like the 1974 U.S. trade act, which prohibits benefits for Ecuador, she would ask them to speak up.

She told reporters that "almost in every case when we start talking with these people and they will say, 'I don't know exactly how to say,' I'll say, 'Listen, you can be blunt - just be blunt.' And after that, they're blunt."