Before July's sweltering temperatures zap us and send all but the most hardy to the beach, there are three more weeks of engagements in June's Datebook. JUNE 12

The annual President's Dinner sponsored by the National Republican Senatorial Committee and the National Republican Congressional Committee has to be at the Washington Convention Center. Where else can you seat 4,000 guests for dinner? The president and vice president are hosts of this $1,500-a-plate event, which falls on President Bush's 66th birthday. Composer Marvin Hamlisch will perform a song especially written for this event, and Dixie Carter, a star of television's "Designing Women," will sing the National Anthem. Dinner proceeds benefit Republican House and Senate candidates. JUNE 14

Secretary of Agriculture Clayton Yeutter and Jeanne Yeutter and the Friends of the National Arboretum are hosts of the private dedication of the Capitol Columns -- 22 columns that were originally part of the east-central portico of the U.S. Capitol and have been restored and installed at the arboretum. A picnic luncheon for invited guests follows. The 10th-anniversary fund-raiser for the Parklands Community Center, a nonprofit, community-based organization serving youths in Southeast Washington, is at the Hyatt Regency Hotel. Tickets are $50. Call 678-6500. JUNE 15

The evening before the June 16 "Race for the Cure," a 5-K run here to promote a national breast cancer awareness campaign, there's a barbecue at the vice president's residence for corporate sponsors of the race, invited guests and celebrities -- including Loni Anderson, Lynda Carter and Larry Hagman. Vice President Dan Quayle and Marilyn Quayle are honorary co-chairman of the 5-K race, 5-K walk and one-mile walk. Proceeds from the race (now $15 per entry) will benefit the Susan G. Komen Foundation, the Nina Hyde Center for Breast Cancer Research and the Greater Southeast Health Care Mammography Program. For race information, call 828-7034. Gabriela Bocec, vice president of Romania's new Family Planning Association and president-elect of the Romanian Nurses Association, is guest of honor at the ninth annual luncheon of the Women's Legal Defense Fund at the Washington Hilton. Bocec is being honored "for her courageous role in family planning" during the Ceausescu years. Gerald McEntee, international president of the American Federation of State, County and Municipal Employees, and John Sweeney, international president of the Service Employees International Union, are also being honored for their support of the Family and Medical Leave Act. Tickets are $75. Call 887-0364. JUNE 16

"Bark Ball III," to benefit the building fund of the Washington Humane Society, is at 9 p.m. at the Hotel Washington. Tickets are $65. Call Diana Kaiser at 638-5900. JUNE 19

Rep. Jim Leach (R-Iowa) discusses "Progressive Internationalism" at the annual membership dinner of the United Nations Association, Capital Area Division, at George Washington University's Marvin Center. Individual tickets are $16.50; tickets for new members are $10. Call 966-5393. JUNE 20

The Children's Inn at the National Institutes of Health, a $5 million, 36-room home-away-from-home for families with children undergoing treatment at NIH, opens June 21. Merck & Co. Inc. is host of a dinner the night before for 400 invited guests at the Children's Inn. Dana Carvey, Gladys Knight, the Gipsy Kings and Crosby, Stills and Nash will perform at the Kennedy Center Concert Hall at "Democrats: The Party of the Decade," a fund-raiser sponsored by Democrats for the 90's (Pamela Harriman's PAC), the Democratic Congressional Campaign Committee and the Democratic Senatorial Campaign Committee. A buffet supper for preferred orchestra and box seat ticket holders follows. Ticket prices range from $30 to $1,000. Funds raised will benefit this year's Democratic campaigns. Call 338-9092. JUNE 21

"Guess Who's Coming to Dinner?," a celebrity dinner that benefits the Whitman-Walker Clinic, which assists AIDS patients in the metropolitan area, begins with a cocktail reception for more than 350 guests at H.H. Leonard's, 2020 O St. NW. Then guests disperse to dinner parties around town with Washington celebrities, among them Burton Lee, physician to the president; Rep. Constance A. Morella (R-Md.); Channel 4's Arch Campbell; and HHS Secretary Louis Sullivan. Tickets are $125. Call 797-3521. JUNE 24

African National Congress Deputy President Nelson Mandela is scheduled to visit Washington June 24 to 26, and plans include his meeting with President Bush (June 25), his address to a joint meeting of Congress, a Congressional Black Caucus Foundation breakfast, and Tuesday night, June 26, a VIP reception and rally at the Washington Convention Center.

JUNE 27

The 24th Festival of American Folklife, co-sponsored by the Smithsonian Institution and the National Park Service, runs from 11 a.m. to 5:30 p.m. June 27 through July 1 and July 4 through July 8 on the Mall. This year's focus is on Senegal, the U.S. Virgin Islands and the "Musics of Struggle" -- "the ways traditional music is being used now to bolster people's enthusiasm and courage," according to Mary Coombs, a Smithsonian spokesman. The opening ceremony at 11 a.m. on June 27 is preceded by a musical program at 10:30. Dance parties are scheduled from 5:30 to 7 every evening except the Fourth of July. Call 357-2700.