Washington: Today - Partly cloudy, highs in low to mid 80s, lows in 60s. Chance of rain is 20 per cent today, 40 per cent tonight. Friday - Partly cloudy with chance of rain, high in 80s.

Maryland and Virginia: Today - Partly cloudy, highs in low to mid 80s, lows in 60s. Chance of rain in west tonight. Friday - Chance of rain, highs in 80s.

Lower Potomac and Chesapeake Bay: Today - Partly cloudy skies with good visibility through tonight. Winds should be variable at less than 7 knots this morning becoming southeasterly at near 10 knots this afternoon through tonight.

Extended Area Outlook: For Saturday through Monday - Partly cloudy Sunday with chance of rain Saturday and Monday. Temperatures should range from Saturday's highs in 80s, lows in 60s to Sunday's and Monday's highs in mid 80s to mid 90s and lows in mid 60s to mid 70s. Washington's normal temperature range for this time of year is from 87 to 67.

Atlantic Ocean Beaches from Cape May through Maryland: Today - Partly cloudy, highs in mid to upper 70s. Friday - Partly cloudy with chance of rain, highs in 70s. Water temperatures should range from low 60s north to upper 60s south both days.

Atlantic Ocean beaches from Cape Hatteras through Virginia: Today - Partly cloudy, highs in upper 70s. Friday - Partly cloudy with chance of rain, highs near 80. Water temperatures should range from upper 60s in north to upper 70s in south both days.

The National Weather Forecast for Today - Showers and thunderstorms will extend from the east portion of the Plains, across the Mississippi Valley, the Ohio Valley and Central Appalachians through the southeast to Include the Gulf Coast and southern Atlantic Coast. Showers will also be scattered over the upper Missouri Valley. Temperatures will be mild over the central Atlantic Coast into the central Appalachians. IT will also be mild over the intermountains, the northern half of the Rockies and upper Missouri Valley. Elsewhere over the nation, temperatures will be generally warm or hot.

ALMANAC DATA FOR JUNE 23, 1977. Sun rises 5:43 a.m., sets 8:37 p.m.; moon rises 12:24 p.m.; sets 12:46 a.m. Tides: High 1:07 a.m. and 1:23 p.m. Low 7:54 a.m. and 8:06 p.m. High and low tides at the following locations can be obtained by subtracting the hours indicated from the tides aboves. Annapolis (3 1/2); Bloody Point Lighthouse (4 1/2); Deale, Md. (4 1/2); colonial Beach (6); Norfolk (1 1/2); Virginia Beach (1); Solomons Island (6 1/2); Point Lookout (7). Pollen count: 26 grass (note: More than 7 or higher is considered undesirable.)

The Council of Governments' Air Quality Index for yesterday showed the high reading in the Washington area during the 2 to 3 p.m. period was 25 for the pollutant, photochemical oxidants. Index values between 25 and 49 indicate fair air quality. When the index exceeds 100 the air becomes hazardous and persons with lung, heart and eye problems should restrict their activity. The forecast for today indicates the air quality will improve.

The National Weather Service forecasts that the Potomac River stage at Little Falls will remain near 3.1 feet through today.

Washington data at 8 p.m. (EDT) yesterday: Highest temperature since 8 a.m. yesterday, 80 degrees at 12:35 p.m. Lowest temperature since midnight, 65 degrees at 5:40 a.m. Deficiency of temperature since June 1, 19 degrees. Excess of temperature since Jan. 1, 189 degrees. Record high temperature for today, 98 degrees in 1874. Record low temperature for today, 51 degrees in 1918. Relative humidity; Maximum, 63 per cent at 11:53 a.m.; Minimum, 38 per cent at 5 p.m. 24-hour precipitation, none. Excess of precipitation since June 1, 76 inches. Deficiency of precipitation since Jan. 1, 5.46 inches. Highest observed wind since 8 a.m. 15 miles per hour from the west-northwest at 1 p.m. Peak gust since 8 a.m., 20 miles per hour from the north at 10:54 a.m. Local Temp., Humidity(TABLE) Time(COLUMN)T.(COLUMN)H. 12midn.(COLUMN)73(COLUMN)53 1 a.m.(COLUMN)72(COLUMN)53 2 a.m.(COLUMN)71(COLUMN)55 3 a.m.(COLUMN)69(COLUMN)59 4 a.m.(COLUMN)66(COLUMN)63 5 a.m.(COLUMN)66(COLUMN)63 6 a.m.(COLUMN)65(COLUMN)63 7 a.m.(COLUMN)68(COLUMN)57 8 a.m.(COLUMN)70(COLUMN)55 9 a.m.(COLUMN)73(COLUMN)50 10 a.m.(COLUMN)76(COLUMN)45 11 a.m.(COLUMN)78(COLUMN)39 12 noon(COLUMN)79(COLUMN)41 1 p.m.(COLUMN)78(COLUMN)41 2 p.m.(COLUMN)77(COLUMN)42 3 p.m.(COLUMN)78(COLUMN)39 4 p.m.(COLUMN)78(COLUMN)39 5 p.m.(COLUMN)79(COLUMN)38 6 p.m.(COLUMN)79(COLUMN)38(END TABLE) Temperatures Abroad Yesterday(TABLE) City(COLUMN)Weather(COLUMN)Time(COLUMN)Temp. Aberdeen(COLUMN)clear(COLUMN)1 p.m. Amsterdam(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)61 Ankara(COLUMN)P.t. cldy(COLUMN)3 p.m.(COLUMN)77 Athens(COLUMN)clear(COLUMN)2 p.m.(COLUMN)88 Auckland(COLUMN)rain(COLUMN)midnight(COLUMN)54 Berlin(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)70 Birmingham(COLUMN)clear(COLUMN)1 p.m.(COLUMN)63 Brussels(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)57 Cairo(COLUMN)clear(COLUMN)2 p.m.(COLUMN)97 Copenhagen(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)73 Copenhagen(COLUMN)pt. cldy(COLUMN)1 p.m.(COLUMN)73 Dublin(COLUMN)clear(COLUMN) 1 p.m.(COLUMN)66 Geneva(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)63 Hong Kong(COLUMN)cloudy(COLUMN)8 p.m.(COLUMN)82 Lisbon(COLUMN)pt. cldy(COLUMN)noon(COLUMN)68 Malta(COLUMN)clear(COLUMN)1 p.m.(COLUMN)63 Manila(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)70 Moscow(COLUMN)clear(COLUMN)1 p.m.(COLUMN)81 Nice(COLUMN)pt. cldy(COLUMN)3 p.m.(COLUMN)59 Oslo(COLUMN)pt. cldy(COLUMN)5 p.m.(COLUMN)106 Paris(COLUMN)clear(COLUMN)1 p.m.(COLUMN)72 Peking(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)63 Rome(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)59 Saigon(COLUMN)pt. cldy(COLUMN)8 p.m.(COLUMN)77 Sofia(COLUMN)cloudy(COLUMN)8 p.m.(COLUMN)86 Stockholm(COLUMN)cloudy(COLUMN)9 p.m.(COLUMN)73 Sydney(COLUMN)cloudy(COLUMN)2 p.m.(COLUMN)75 Tel Aviv(COLUMN)Clear(COLUMN)8 p.m.(COLUMN)82 Tokyo(COLUMN)clear(COLUMN)3 p.m.(COLUMN)97 Tunis(COLUMN)clear(COLUMN)2 p.m.(COLUMN)88 Vienna(COLUMN)cloudy(COLUMN)9 p.m.(COLUMN)63 Warsaw(COLUMN)clear(COLUMN)1 p.m.(COLUMN)82(END TABLE) Temperatures (Western Hemisphere)(TABLE) City(COLUMN)Weather(COLUMN)High(COLUMN)Low Acapulco(COLUMN)pt. cldy(COLUMN)90(COLUMN)79 Barbados(COLUMN)pt. cldy(COLUMN)86(COLUMN)78 Bermuda(COLUMN)rain(COLUMN)85(COLUMN)75 Calgary(COLUMN)cloudy(COLUMN)79(COLUMN)59 Cudiacan(COLUMN)fair(COLUMN)94(COLUMN)75 Edmonton(COLUMN)pt. cldy(COLUMN)75(COLUMN)52 Havana(COLUMN)clear(COLUMN)90(COLUMN)77 Kingston(COLUMN)fair(COLUMN)91(COLUMN)31 Montego Bay(COLUMN)clear(COLUMN)90(COLUMN)75 Mexico City(COLUMN)cloudy(COLUMN)72(COLUMN)54 Monterrey(COLUMN)pt. cldy(COLUMN)94(COLUMN)70 Montreal(COLUMN)rain(COLUMN)73(COLUMN)46 Nassau(COLUMN)fair(COLUMN)88(COLUMN)77 Ottawa(COLUMN)cloudy(COLUMN)72(COLUMN)52 Regina(COLUMN)cloudy(COLUMN)77(COLUMN)59 St. Kitts(COLUMN)pt. cldy(COLUMN)86(COLUMN)78 Toronto(COLUMN)clear(COLUMN)75(COLUMN)50 Vancouver(COLUMN)clear(COLUMN)61(COLUMN)50 Veracruz(COLUMN)cloudy(COLUMN)86(COLUMN)74 Winnipeg(COLUMN)pt. cldy(COLUMN)77(COLUMN)57(END TABLE)