Where America is rehearsing for the 21st century

Florida, it is said, is the only state that becomes more Southern the further north you go. Miami is sometimes referred to as ''New York with palm trees,'' especially by people outside Miami. Parts of the Panhandle are widely known to Floridians farther south as ''lower Alabama'' or ''southern Georgia.''

It's almost as if Florida were a miniaturizing mirror, reflecting the US as a whole, with north and south flip-flopped. The analogy like this shouldn't be pushed too hard, but this one holds up fairly well; Florida even has a ''Midwest'' in the central part of state, and two coasts, east and west.

But Florida's development is being watched for reasons more profound than a clever map trick. Florida is in many ways the place where America is rehearsing for the 21st century: in its flourishing ''new industries,'' in its demographic mix, and in the way it has exploited sunshine as an economic resource, among others. As anyone who has read an airline in-flight magazine in the last few months probably knows by now, Florida is one of five ''bellwether'' states identified by futurologist John Naisbitt, author of ''Megatrends.''

Mr. Naisbitt cites several reasons to keep an eye on Florida for hints of the shape of things to come.''For one thing, the state has a very dynamic economy, resting on new industry: It's an information-electronics economy.''

He is emphatic that ''sunrise'' industry will be an essential part of a dynamic ''new economy'' in the United States.

With its high proportion of retirees, Florida today has the same mix of age groups that the country as a whole will have in 1995, and may provide some clues as to what the ''graying of America'' will be like. As the state copes with needs for new roads, bridges, sewers, and schools, for example, we will see whether retirees will pass bond issues to fund capital projects with 30-year payoffs.

The much-vaunted internationalization of Florida is certainly real, particularly around Miami, but it may be even more apparent than real. The Hispanic concentration in south Florida gets diluted by the more resolutely Anglo parts of the state, giving the state as a whole a total proportion of Hispanics only slightly higher than the national figure.

But many Florida-watchers see here in Spanish-speaking Miami the first instance of another language finding an equal footing with English in the US. Instead of being the language of an ethnic enclave excluded from the power structure, Spanish is the language of big deals, of international trade.

In this Mr. Naisbitt finds illustration of his thesis of the shift from a national to a global economy, and also for the ''renaissance in language and cultural assertiveness'' he predicts will accompany this globalization.

Florida's rise also illustrates the increased value now placed on ''quality of life.'' Sunshine has been economically quantified. The new industries, electronics and other high-technology endeavors, can be located anywhere; transportation costs are relatively insignificant, so distance to market is not a consideration. Nor is access to natural resources.

What's really important is for these brain-intensive ''sunrise'' industries to locate in places where bright young engineers will want to raise their families. High-tech firms generally define ''quality of life'' as some combination of good schools, reasonable housing costs, pleasant climate, and good cultural and recreation opportunities.

Of these, climate and recreation are Florida's great strengths. The climate that has made Florida the most popular tourist destination in the Western hemisphere, and No. 2 in the whole world, behind Spain, has become part of the basis for Florida's electronics industry. If you liked two weeks at Disney World , you'll love 52 weeks in one of our industrial parks, the theory goes.

Since World War II, Florida has tended to be last in, last out of a recession. But observers around the state are ''pragmatically optimistic,'' to borrow a phrase from Gov. Bob Graham, that the state will break out of that pattern, and be last in, first out of the current doldrums.

In fact, John M. Godfrey, vice-president and chief economist of the Barnett Banks in Jacksonville, maintains, ''We popped out of this recession last summer.'' This will come as a surprise to some, including the governor, who told the Monitor, ''We didn't feel the recession till late 1982.''

Traditionally, Florida booms have been generated by real estate activity, which has been dependent on outside money pouring into the state during times of general national prosperity. The boom of the 1920s was the classic example. Its legacy is in the relentless rectilinear geometry of the numbered streets and avenues of towns laid out all at once with a few quick strokes of a draftsman's pencil against a T-square.

Despite the diversification of recent years Florida is still dependent on outside factors. ''But the outside factors have been pretty good'' lately, Mr. Godfrey says.

Inmigration has continued at 2 percent annually. ''That kind of growth really drives a state forward,'' he says. By 1990, if not before, Florida is expected to overtake Ohio, Illinois, and Pennsylvania - which have all lost many residents to Florida - to become the fourth-most-populous state.

Hank Fishkind, an economist at the University of Florida in Gainesville, concurs heartily, projecting inmigration to continue at 250,000 yearly through the 1980s.

Other bright spots: falling interest rates, which have made it easier for would-be retirees to sell their homes and move south, and strong tourism in late 1982.

Real estate has become a little more rational. The boom of the early '70s, in the classic Roaring '20s pattern, was followed by a recession that saw Florida stuck with a huge surplus of housing hanging over the market. But that overbuilding was not repeated during the next boom, in 1979, and Dr. Fishkind thinks people may have learned a lesson. He also projects housing starts at 195, 000 this year.

Unemployment has risen, rather sharply in fact, in recent months (it was 9.7 percent, adjusted, in February), prompting mutterings around the state about what a lagging indicator jobless rates are.

Mr. Godfrey says net employment growth is a much sounder index of economic health than unemployment rates. Florida's employment was up 5.5 percent this past November over the year before. This measure shows Florida leaving the rest of the country in the dust. Only 10 of the 50 states had positive growth in employment from November to November, and national employment was off 1 percent. (Vermont, however, came in second in this race, with 2.8 percent jobs growth, a reminder that there is life outside the Sunbelt.)

Trying to get past statewide statistics for a real closeup of Florida is like trying to fit all the members of a large family into your viewfinder to make one snapshot: Just when you get everybody squeezed in somehow, somebody moves.

Lester Freeman, senior vice-president of Southeast Bank in Miami, observes: ''If you want to think of Florida as a whole, you simply can't focus. It's all over the map.''

Traditionally, Florida's top three industries have been tourism, citrus, and phosphate, which is mined and made into fertilizer. Retirement functions as another major export industry. Governor Graham has spearheaded a big push to expand the state's growing electronics sector. Florida is a major state for defense contracting (which is largely electronics nowadays) and for the aerospace industry as well.

The consumption orientation of the economy is unmistakable. The large numbers of retirees, plus the 40 million tourists that pass through here in a year, mean that there are lots of people who need to be fed, lodged, and outfitted in alligator shirts, but who don't need jobs. In short, they consume but don't produce. Health care is also big business in Florida, partly because of the numbers of older people. Affluent Latin Americans stream into Miami for medical treatment.

Southeast Florida is relatively depressed, by its own standards at least. Miami is feeling pinched by deteriorating trade with Latin America, the result of recession in those countries. J. Antonio Villamil, vice-president and chief international economist at Southeast Bank of Miami, says, ''The international sector this year will be a drag on economic activity in south Florida.''

Dade County (Miami) is projected to grow by 15,000 a year through the 1980s, half the growth of the '70s. Broward and Palm Beach counties, to the north, are feeling the same pinch, but have more electronics industry to offset it.

Florida's southwest coast is enjoying a surge of growth, helped along by the opening of a new stretch of Interstate 75. Dr. Fishkind is one of many who compare this area today with the way the Miami area was 15 or 20 years ago - on the verge of explosive growth, and perhaps of repeating Miami's mistakes. Officials say that won't happen, but after experiencing traffic on both coasts this correspondent is hard put to find one a qualitative improvement over the other.

The cities of the electronics belt, from Tampa and St. Petersburg across to Orlando and down the east coast to Melbourne, have generally done well, as a result of tourism, retirement, defense contracts, and electronics industry, with slightly different mixes in each place.

Jacksonville, a banking and insurance center, has enjoyed steady but sure growth, though somewhat overshadowed by its more glamorous sisters to the south.

If Florida is so terrific, why did it take this long to take off? Why was it so sleepy for so long?

Improved transportation has helped, as has new legislation to improve the state's business climate. Schools and universities here have frankly been seen as a liability rather than an asset, although there are signs of improvement.

And ironically, one of the drawbacks was climate. Sunshine is great, but what about humidity? There are those who maintain that Florida's boom would have been impossible without central air conditioning. ''It is no more pleasant to be here in summer without air conditioning than it would be to be in New England in winter without central heat,'' Dr. Fishkind, an erstwhile Bostonian, says.

In the brisker climate of the new, dehumidified Florida, things move at a faster pace. Investment firms that once flew brokers in one at a time from New York to counsel the dowagers of Miami Beach now have offices here - on every street corner, it seems.

Geoffrey Trafford, the youthful manager of the Fort Lauderdale office of Midland Doherty Inc., sketches in Florida's future as full of bright young baby-boomers scrambling up the ladder, earning more and demanding more, notably in the financial-services sector. Individuals and firms will have to find their own niches in a fiercely competitive environment. ''If you hope to maintain quality, you can't be all things to all people. You have to find something that distinguishes you from the herd,'' he adds, cocking an eyebrow just enough to make sure the visitor gets his point.

Twenty-first century, here we come.