Hawaii is the favorite destination for American travelers, winter or summer - not that seasons matter much on the palm-fringed, sea-kissed islands where the average high in the "coldest" months, January and February, is 79, and in the hottest months, July, August and September, 87.

Regardless of what the calendar says, more American travelers want to go to Hawaii than anywhere else in the world, according to American Express Travel Related Services Co., which conducted a survey of its member agents.After Hawaii, the top destinations in the survey are the Caribbean; Mexico; Florida; Nevada; the United Kingdom; Colorado; Continental Europe; California; and the Bahamas. The Caribbean scored well despite Hurricane Gilbert, which swept through Jamaica and Mexico's Yucatan Peninsula, and skirted the Cayman Islands, in September.

The choicest U.S. cities picked by winter travelers in the survey are Honolulu; San Francisco; New York; New Orleans; Washington, D.C.; Boston; Chicago and Houston (tie); and Atlanta and Dallas (tie).

Respondents said the key reason for winter vacations is "to escape from bad weather," hence the popularity of sunshine destinations. These factors were cited as the most important in choosing a destination: the "allure" of the destination, quality of service, lowest price, security, availability of nightlife and entertainment, whether all expenses were included in the package, variety of sports nearby, shopping, opportunity to meet people and planned activities.

What about the year ahead?

Will history-rich Europe, always a favorite with American travelers, continue to be popular in 1989, despite high prices aggravated by a weak U.S. dollar? Will Mexico, the land of sunny beaches and Mayan ruins, remain a "hot" destination, thanks to proximity, ease of access and bargain prices fueled by a devalued peso? Will cruise ships, offering the unique travel experience of a floating hotel, continue to attract crowds?

Several travel agents in Atlanta looked into their crystal balls to predict what the fresh new year might mean to travelers. Their conclusions, the personal opinions of people whose business is arranging vacation and business travel for a broad base of clients, are not intended to be a comprehensive survey. More than one agent cautioned that everything is subject to change, depending on money matters, politics, even weather (who, for example, could have predicted Hurricane Gilbert, which lashed Jamaica and Mexico's Yucatan Peninsula last September, causing a sudden collapse in visitor arrivals).

Here's what the agents predict for 1989:

Cruises: "Cruises are still the hot item for value," said Philip Osborne, president of Osborne Travel. "There are so many ships on the market that competition is strong and values are good. For 1989, Mediterranean cruises will be the best way to visit the southern tier of Europe, especially while the U.S. dollar is weak."

Stephanie Laney, vice president and general manager of Laney International Travel in Acworth, agreed, saying Caribbean cruises are "always popular." She cited Royal Caribbean Cruise Lines as an example:

"The seven-day programs will average $1,655 per person during peak season, or $236 per person per day. Value season will average $1,570 or $224 per person per day. Everything is included: round-trip airfare from home to Miami, round-trip transfers to and from the pier, seven nights aboard the ship and all meals and all entertainment. The individual components for a land package at a top-notch hotel would likely cost almost double that per person, per day, for the exact same features."

Short cruises are likely to be popular in 1989 and are not limited to the traditional Caribbean market from South Florida, said Dolores Davis, assistant to the general manager of Rich's Travel Agency: "Ocean Cruise Lines offers seven-day cruises in Europe for those people who have only one week, and can be combined with a land tour."

American Express, surveying its five travel managers in Atlanta, also expressed confidence in the outlook for cruises, crediting one company in particular for its aggressive promotion. "Cruises are an incredible value. One price pays for it all: airfare, transfers, the cruise, meals and entertainment. Carnival Cruise Line has done great publicity for the cruise industry, getting rid of the blue-hair image of cruise passengers. People are beginning to understand cruising is affordable. This can't do anything but grow. It's basically an untapped market."

Package tours: The fixed cost of package tours makes them a good buy, in the opinion of James F. Buckle of Duffy Travel Service. "With almost everything prepaid, this is a hedge against currency fluctuations," he said.

American Express, a leader in the package tour industry, also pointed out the value such tours offer: "American Express is the only tour operator guaranteeing the dollar rate will not fluctuate." And tours are becoming more varied, offering alternatives to escorted groups following rigid schedules, according to American Express: "European independent city packages allow travelers to follow a basic trip outline, but without cattle calls. The prices are bought in group space rates yet are available on a `go any day' basis."

Traditional favorites: Year after year, some parts of the world attract swarms of Americans, and will continue to do so, the agents say.

"Hawaii is always popular, exotic but still a part of the U.S.A.," said Ms. Davis of Rich's Travel.

"The Caribbean and Mexico will continue to grow in popularity," the American Express managers predicted. "Why? Because quick trips can be purchased at the last minute, including charters and cheap specials for three or four nights. This fits Americans' 1980s lifestyles."

"Europe in general will remain popular," said Ms. Laney. "Even with the dollar down, terrorism is not the threat it was in the middle 1980s. Thus people who postponed their European trips are making plans to visit in 1989. The dollar is actually where it was in 1981 and 1982 before its unprecedented rise beyond reality."

Cancun, Mexico and cruises in Alaska are perennially popular and will remain so in 1989, Buckle said. Alaska cruises are popular because of value, he said.

"There are already special reductions on the early and late season cruises," he said.

With the exception of Japan, where the powerful yen makes prices high for Americans, the Orient will continue to appeal to many vacationers, according to Manny Beauregard, president of Hallmark Travel.

"The Orient still holds all the mystery and charm for Westerners that existed when we only had National Geographic to tell us about it," he said. "The traveling public has realized the values to be found in places like Hong Kong, Thailand, Singapore and Indonesia. Although it's a long way to travel from Atlanta, luxury hotels can be had for less than $200 a night, and the dollar can be stretched a long way when duty-free shopping in these bargain capitals of the world. Japan, unfortunately, is just too expensive for the average tourist."

Off the beaten path: Several agents expect the Soviet Union to become even more popular with seasoned travelers this year, sparked by friendlier relations between the governments of the United States and the Soviet Union. Africa and Eastern Europe also will have wider appeal, they predicted.

Hugh Hosch, president of Hosch Far Horizons, agreed: "The 1988 boom will become a landslide in 1989, with the emphasis on new destinations within the Soviet Union."

The opinion was echoed by Osborne: "Russia is hot now and getting hotter."

In the opinion of several agents, Africa is likely to attract a new wave of adventure travelers. "Tanzania will be popular in 1989 because many people have been to Kenya and now are willing to experience less luxury in order to see more game and fewer tourists, Ms. Davis said. "Tanzania offers excellent game photography."

"Tanzania and Rwanda continue to be strong destinations," Osborne said. "With the popularity of the book and film `Gorillas in the Mist,' both countries are expected to be hot."

Eastern Europe also will appeal to travelers, Hosch predicted.

"First, it is still a relatively unknown part of Europe for most Americans, but will get increased interest as it rides the coattails of the U.S.S.R. boom. Second, it is cheaper than Western Europe by a good margin."