June came vigorously to Washington yesterday, bringing the summer season's first wave of water sport in reopened city pools; cowboys and horses parading down Pennsylvania Avenue for an annual urban rodeo, and the pounding competition of a double-dutch rope jumping tournament at Dunbar High School.

It was a weather-perfect day for outdoor activity, with temperatures rising to a midday high of 83 with 15 mph winds under a benevolent sun.

At the D.C. Stadium Armory, preparations were under way for the Bill Pickett Invitational Rodeo, named for a turn-of-the-century black cowboy credited with originating the rodeo event of "bulldogging" cattle. Many of the Wild West-style participants paraded through downtown D.C. behind the blaring trumpets of the Kelly Miller Junior High School Marching Band. Men and women in dungarees, bandannas and western boots rode tall in the saddle, shouting "yee haw" to the thin crowds while holding onto their cowboy hats against the breeze.

Riders in the parade included the Ebony Horse Women Inc., an all-black women's riding group, and six brown Belgian horses representing the sponsor of the rodeo, Aldolph Coors brewery.

Moses Brewer, a representative for Coors, said the traveling rodeo is a salute to black cowboys and the contributions they have made to the West.

"Many blacks are not aware of the work men like Bill Pickett have done, and through the rodeo we hope to . . . make them aware of these accomplishments," Brewer said.

For those who sought wet relief from yesterday's warm temperatures, many of the city's pools were opened for the season. Charles Simobi, assistant manager at the Randall Recreation Center in Southwest, said that while the crowd reached nearly 100 during midafternoon yesterday, he expects to see many more people after schools close.

Jeff Williams, 11, splashing around in the Randall pool with dozens of other youngsters, said he was glad to see the pool open because "it's a good place to cool off when it's hot."

Meanwhile, entrants in the District's double-dutch rope jumping contest competed for the right to move on to the national competition this month in Philadelphia.

Double-dutch, long a summer tradition among children, especially in neighborhoods where streets are the playgrounds, is a tougher version of plain rope jumping in which two ropes are turned alternately in opposite directions. The talent displayed in yesterday's contest, sponsored by the D.C. Metropolitan Police and McDonald's, ranged from speed jumping to jumping rope while simultaneously jumping through a Hoola-Hoop.

Entrants, representing their schools in grades four through nine, were judged on execution, originality, difficulty and overall performance.

Loleata Griffin, 10, of the Clark Elementary School "Superstars," said she and her teammates were nervous during the competition. She said they have been practicing intensely for five weeks. The girls, all age 10, have been jumping together for two years and placed second in last year's citywide competition.

"We just keep looking at the trophies and saying, 'We're going to win,' " Griffin said.