It was the last and longest Sunday of spring yesterday, an ideal day of bright, warm sunshine and crisp, fresh breezes, and it set a wonderful meteorological example for the new season that starts today.

Summer, which many Washingtonians regard warily and often justly as a time of atmospherically induced torment, arrives here at 1:23 p.m., for a run of 94 days.

Today is the longest day of the year, with 14 hours and 54 minutes between sunrise and sunset. Yesterday was one minute shorter.

The new season follows a cool spring in which the temperature reached 90 degrees only once.

Today is expected to be "pretty warm," with highs from 80 to 85, said forecaster Gary Ellrod, but Tuesday is expected to be about five degrees cooler, a day much like yesterday with its pleasant high of 80.

Under blue skies dotted here and there with benign and unthreatening clouds, Washingtonians pedaled bicycles along the Potomac River, picnicked in parks, flung frisbees, flew kites, played softball and hardball, and found a variety of other ways to delight in 14 hours and 53 minutes of daylight under a blanket of comfortably dry Canadian air.

Some outdoor activities were marked by tragedy, however. Thomas C. Perfetti, 32, of Gaithersburg, was killed when his hang glider crashed near Hagerstown, Md., authorities said. Two men were reported missing in the Potomac. Thomas B. Sterman, 19, of Northwest Washington, went under while swimming near Great Falls, and an unidentified man vanished in the river after his canoe capsized near Little Falls, authorities said.