This is the highest of Washington's high season -- the time every fourth spring when the quadrennial political cycle, the peak of annual visitor traffic, and the short weeks of horticultural splendor coincide.
Hotels are almost inhospitably overbooked.
Busloads of tourists come to see the sights. Americans' fascination with their nation's capital, the root-place of their political system, appears to grow despite complaints that federal leaves and branches are intruding into their lives. Through the 1970s, overall visitor growth in Washington averaged 5 percent a year -- reaching about 13 million last year.
The busiest time of any tourist year is the post-Easter weeks -- and normally the single busiest night is the first Tuesday after Easter, when youths on spring recess meet coming and going.
Crowds are drawn to the Washington blossom festival that spills into its suburbs. The pale frost of cherry and other fruit blossoms, then the airy pointillist clouds of dogwood, give way to the absolute apex of Washington color -- its azaleas. By summer, Washington subsides into the relentless heat and overgrowth of green until its flicker of autumn yellow.
Neatly, the Washington visitor pattern fits the cycle of natural attraction: a surge from mid-MArch to June, a softening from July to mid-September, then a gain until December, and a falloff to Janury's nadir.
Nature's role in the capital's allure is deceiving. It is accentuated by the political tides, the two-year and, particularly, the four-year election rounds.
After an election, people with a stake in the outcome -- the business and trade, farming, education, and other interest groups -- come to town early in a new administration or Congress to find out what it means to them.
"The four-year surge is not keyed to who is in the White House," says Austin Kenney, executive vice-president of the Washington Convention and Visitors Association. It is a nonpartisan curiosity. It occurs for every new president and Congress.
This spring, Washington is extraordinarily crowded because of the magnitude of the Reagan administration's attempt to change federal spending and governing patterns.
In tourism, at least, if historical patterns prevail, it will be downhill from here for Mr. Reagan.
But mostly an innocent patriotism seems to attract Americans to Washington, not partisan or special-interest concerns.
"You will tell your grandchildren you were eating lunch on the White House lawn," a young man tells his companion.
The crowds outside the White House gates take each others' pictures, the famous home and office in the background. From Lafayette Park, across Pennsylvania Avenue -- a park that shows Lady Bird Johnson's touches in the tulip beds, the trimmed horse chestnuts -- shooting right the tourist can get President Jackson on a rearing horse, the White House, and the Washington Monument all in one frame.
Families, couples, a few vaguely vagrant travelers alone, Asian, European, Latin, visitors circulate in the capital with a deferential, if not reverential, air.
They pass the White House gate, stare between the iron fence spikes to absorb the scene, with little apparent sense of the inhabitant.
But, like pigeons aflutter, their pulses surge when a limousine comes and goes, or police stop traffic on a late Sunday morning when the President or vice-president attend church at St. John's, across Lafayette Park.
Whatever their complaints about its government, Americans love their capital, and the four-year, spring visitor surges are expected to swell in the future.
Nearly 5 million visitors a year now stay in area hotels, and about an equal number stay with friends and families, visitor host Kenney says. Another 3 million or 4 million visitors just dip into town for the day and leave.
Washington already has the fourth-largest concentration of hotel rooms -- 36, 000 at last count -- in the nation, behind New York, Chicago, and Las VEgas. And rapid downtown and suburban hotel expansion -- possibly 5,000 or 6,000 more rooms -- is expected over the next five years.
Washington also will get a new convention center. The $100 million project downtown will be finished at the end of 1982 and is expected to a dd $100 million yearly to the capital's one-third of a billion-dollar convention business.