LIKE TALL PEOPLE, who go through life being asked about "the weather up there," native Washingtonians expect the comment, "Really? I didn't think anyone was ever actually born here." Now, even the hastiest research indicates that births have been recorded here every day for as long as anyone can remember, leap years included. Far more interesting -- and the subject of sophisticated research -- are the findings of demographers Eunice and George Grier concerning who lives in Greater Washington today and how patterns of living have changed over the years. As indicated in an article on the opposite page, the makeup of the region and its households has undergone dramatic shifts that mean different attitudes, interests and plans on the part of people throughout the metropolitan area.

A remarkable upsurge of adults-only households, for example, is having important effects on everything from school closings to downtown rebuilding and demands for housing. The Griers' research, based on U.S. Census figures to 1977, not only points up changes in the Washington area of today, but suggests that in them are the ingredients for discontent among groups of people in the years ahead. Without making predictions, the Griers note that a potential for tension exists in what is becoming a "two-class society" of rich alongside poor in the central city as a black and white middle class continues to move outward.

Adding to the anxieties of poorer people are the displacements caused when the "new urbanities" move into neighborhoods. There is understandable concern among poorer blacks, too, about the new minorities -- largely Asians and Hispanics -- whose education, income levels and economic successes show them to be better off.

Another important question arises: what will happen to public schools as their constituencies dwindle? The emphasis on schools may simply move out with the people: an earlier study by Carol L. Richards for the Greater Washington Research Center showed increases in school populations in the "fringe" areas outside of what has been considered the Greater Washington region.

The Grier report does note some hopeful signs, too. The Washington area and its residents "come equipped" with far more resources -- money, facilities, educational attainment and "all the prerequisites of success" -- than they had 10 years ago. With continued success and expansion of regional cooperation, Washington can continue to thrive.