Washington: Today - Partly cloudy, high in 50s, low in low to mid 40s. Chance of rain is 10 per cent today, 30 per cent tonight. Wednesday - Mostly sunny, high in mid to upper 60s.

Maryland and Virginia: Today - Partly cloudy, high in low to mid 60s, low tonight mid 30s to mid 40s. Chance of light rain today. Wednesday - Mostly sunny, highs in mid 50s to upper 60s.

Lower Potomac and Chesapeake Bay: Today - Partly cloudy with chance of light rain and visibility ranging from good to poor. Winds should be westerly at 20 knots today, decreasing to 10 knots or less tonight.

Extended Area Outlook: For Thursday through Saturday - Chance of rain Thursday followed by partly cloudy skies through the remainder of period. Washington's normal temperature range for this time of year is from 72 to 50.

The Nation Yesterday: Shower and thundershower activity decreased in the east yesterday evening and showed a considerable decrease. The early evening activity was widely scattered to scattered over the mid Atlantic Coast states, the Carolinas, the Ohio Valley region and from southeastern Michigan into western Pennsylvania and western New York. Showers were also found in Illinois, Arkansas, northwest Texas, New Mexico and along the central and eastern Gulf Coast. New activity in the form of scattered showers developed from northern California through western Washington. Isolated showers and thundershowers develped in the southern and central plateau and central Colorado. With light winds and fair skies, local frost was expected to occur in the upper and mid Mississippi and the lower and mid Ohio Valleys last night. A frost warning was issued for southern Lower Michigan, Williston, N.D. reached 84 degrees yesterday afternoon breaking the old record high for April 25th of 83 set in 1952. Warm weather also occurred in the northern half of the Rockies and over most of the Plateau region including eastern Washington and the deserts of southern California.

The National Weather Forecast for Today - Most of the nation will be sunny. Showers will be scattered over Washington state and northern Oregon into the northern Rockies and also over the central and northern Appalachians and the lower Ohio Valley region. Except for mild temperatures in Florida and the upper Great Lakes region, it will be cool east of the Mississippi River. It will be warm over the upper Mississippi Valley and the northern Plains into the northern half of the Rockies. The rest of the nation will have seasonal temperatures.

The Council of Governmens' 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 3.8 feet today.

Washington data at 8 p.m. (EDT) yesterday: Highest temperature since 8 a.m. yesterday, 70 degrees at 4:10 p.m. Lowest temperature since midnight, 51 degrees at 5:45 a.m. Excess of temperature since April 1, 132 degrees. Excess of temperature since Jan. 1, 113 degrees. Record high temperature for today, 94 degrees in 1915. Record low temperature for today, 34 degrees in 1883. Relative humidity: Maximum, 83 per cent at 5 a.m.; minimum, 47 per cent at 4 p.m. 24 hour precipitation, trace.

Excess of precipitation since April 1, .10 inches. Deficiency of precipitation since Jan. 1, 3.97 inches. Highest observed wind since 8 a.m., 12 miles per hour from the n.w. at 9 a.m. Peak gust since 8 a.m., 23 miles per hour from the n.w. at 6:25 p.m. Local Temp., Humidity(TABLE) Time(COLUMN)T.(COLUMN)H. 12 midn.(COLUMN)57(COLUMN)78 1 a.m.(COLUMN)57(COLUMN)78 2 a.m.(COLUMN)56(COLUMN)77 3 a.m.(COLUMN)55(COLUMN)77 4 a.m.(COLUMN)54(COLUMN)77 5 a.m.(COLUMN)52(COLUMN)83 6 a.m.(COLUMN)51(COLUMN)83 7 a.m.(COLUMN)46(COLUMN)76 8 a.m.(COLUMN)54(COLUMN)74 9 a.m.(COLUMN)57(COLUMN)64 10 a.m.(COLUMN)60(COLUMN)62 11 a.m.(COLUMN)62(COLUMN)56 12 noon(COLUMN)64(COLUMN)56 1 p.m.(COLUMN)66(COLUMN)52 2 p.m.(COLUMN)65(COLUMN)54 3 p.m.(COLUMN)68(COLUMN)51 4 p.m.(COLUMN)69(COLUMN)47 5 p.m.(COLUMN)68(COLUMN)55 6 p.m.(COLUMN)66(COLUMN)52(END TABLE) Temperatures ending 8 p.m. (EDT) yesterday.(TABLE) City(COLUMN)L.(COLUMN)H. Albany(COLUMN)41(COLUMN)48 Albuquerque(COLUMN)48(COLUMN)74 Amarillo(COLUMN)49(COLUMN)73 Anchorage(COLUMN)41(COLUMN)48 Asheville(COLUMN)44(COLUMN)62 Atlanta(COLUMN)48(COLUMN)67 Atlantic City(COLUMN)46(COLUMN)53 Austin(COLUMN)59(COLUMN)77 Baltimore(COLUMN)47(COLUMN)68 Billings(COLUMN)36(COLUMN)75 Birmingham(COLUMN)50(COLUMN)68 Bismarck(COLUMN)25(COLUMN)78 Boise(COLUMN)54(COLUMN)87 Boston(COLUMN)42(COLUMN)46 Brownsville(COLUMN)56(COLUMN)86 Buffalo(COLUMN)39(COLUMN)47 Burlington, Vt.(COLUMN)38(COLUMN)45 Casper(COLUMN)33(COLUMN)71 Charl'ton, S.C.(COLUMN)58(COLUMN)72 Charl't'n, WVa(COLUMN)44(COLUMN)53 Charlotte, N.C.(COLUMN)44(COLUMN)70 Cheyenne(COLUMN)35(COLUMN)64 Chicago(COLUMN)42(COLUMN)56 Cincinnati(COLUMN)35(COLUMN)48 Cleveland(COLUMN)42(COLUMN)50 Columbia, S.C.(COLUMN)46(COLUMN)77 Colu'bus, Ohio(COLUMN)39(COLUMN)48 Dal.-Ft. Worth(COLUMN)51(COLUMN)75 Dayton(COLUMN)37(COLUMN)52 Denver(COLUMN)42(COLUMN)69 Des Moines(COLUMN)43(COLUMN)65 Detroit(COLUMN)41(COLUMN)45 Duluth(COLUMN)29(COLUMN)63 El Paso(COLUMN)51(COLUMN)78 Fairbanks(COLUMN)35(COLUMN)44 Fargo(COLUMN)28(COLUMN)72 Great Falls(COLUMN)36(COLUMN)79 Hartford(COLUMN)42(COLUMN)56 Helena(COLUMN)35(COLUMN)80 Honolulu(COLUMN)67(COLUMN)80 Houston(COLUMN)61(COLUMN)78 Indianapolis(COLUMN)36(COLUMN)49 Jackson, Miss.(COLUMN)52(COLUMN)71 Jacksonville(COLUMN)57(COLUMN)80 Juneau(COLUMN)35(COLUMN)62 Kansas City(COLUMN)40(COLUMN)65 Las Vegas(COLUMN)62(COLUMN)95 Little Rock(COLUMN)44(COLUMN)68 Los Angeles(COLUMN)55(COLUMN)74 Louisville(COLUMN)41(COLUMN)58 Memphis(COLUMN)49(COLUMN)67 Miami Beach(COLUMN)66(COLUMN)87 Midland(COLUMN)51(COLUMN)75 Milwaukee(COLUMN)41(COLUMN)49 Mpls.-St. Paul(COLUMN)34(COLUMN)63 Nashville(COLUMN)46(COLUMN)62 New Orleans(COLUMN)55(COLUMN)79 New York(COLUMN)42(COLUMN)56 Norfolk(COLUMN)58(COLUMN)68 North Platte(COLUMN)30(COLUMN)68 Okla. City(COLUMN)40(COLUMN)71 Omaha(COLUMN)36(COLUMN)68 Orlando(COLUMN)62(COLUMN)82 Philadelphia(COLUMN)50(COLUMN)67 Phoenix(COLUMN)69(COLUMN)95 Pittsburgh(COLUMN)41(COLUMN)53 Portland, Me.(COLUMN)35(COLUMN)42 Portland, Ore.(COLUMN)51(COLUMN)70 Providence(COLUMN)42(COLUMN)48 Raleigh(COLUMN)46(COLUMN)70 Rapid City(COLUMN)36(COLUMN)69 Reno(COLUMN)45(COLUMN)72 Richmond(COLUMN)53(COLUMN)71 St. Louis(COLUMN)38(COLUMN)64 St. Prg.-Tam.(COLUMN)66(COLUMN)80 Salt Lake City(COLUMN)48(COLUMN)83 San Antonio(COLUMN)52(COLUMN)79 San Diego(COLUMN)56(COLUMN)72 San. Fran.(COLUMN)55(COLUMN)63 San Juan, P.R.(COLUMN)72(COLUMN)87 St. Ste. Marie(COLUMN)38(COLUMN)55 Seattle(COLUMN)52(COLUMN)70 Shreveport(COLUMN)52(COLUMN)74 Sioux Falls(COLUMN)35(COLUMN)64 Spokane(COLUMN)61(COLUMN)85 Syracuse(COLUMN)43(COLUMN)49 Topeka(COLUMN)39(COLUMN)67 Tucson(COLUMN)61(COLUMN)87 Tulsa(COLUMN)41(COLUMN)71 Washington(COLUMN)51(COLUMN)70 Wichita(COLUMN)39(COLUMN)67(END TABLE) Temperatures Abroad Yesterday(TABLE) City(COLUMN)Weather(COLUMN)Time(COLUMN)Tem. Aberdeen(COLUMN)drizzle(COLUMN)1 p.m.(COLUMN)46 Amsterdam(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)52 Ankara(COLUMN)pt. cldy.(COLUMN)3 p.m.(COLUMN)64 Athens(COLUMN)clear(COLUMN)2 p.m.(COLUMN)66 Auckland(COLUMN)clear(COLUMN)midnight(COLUMN)48 Berlin(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)48 Birmingham(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)55 Brussels(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)46 Cairo(COLUMN)clear(COLUMN)2 p.m.(COLUMN)79 Casablanca(COLUMN)cloudy(COLUMN)noon(COLUMN)70 Copenhagen(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)45 Dublin(COLUMN)drizzle(COLUMN)1 p.m.(COLUMN)50 Geneva(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)59 Hong Kong(COLUMN)clear(COLUMN)8 p.m.(COLUMN)81 Lisbon(COLUMN)pt. cldy.(COLUMN)noon(COLUMN)72 London(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)57 Madrid(COLUMN)clear(COLUMN)1 p.m.(COLUMN)77 Malta(COLUMN)clear(COLUMN)1 p.m.(COLUMN)68 Manila(COLUMN)clear(COLUMN)8 p.m.(COLUMN)84 Moscow(COLUMN)cloudy(COLUMN)3 p.m.(COLUMN)59 New Delhi(COLUMN)clear(COLUMN)5 p.m.(COLUMN)102 Nice(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)64 Oslo(COLUMN)clear(COLUMN)1 p.m.(COLUMN)48 Paris(COLUMN)cloudy(COLUMN)1 p.m.(COLUMN)59 Peking(COLUMN)cloudy(COLUMN)8 p.m.(COLUMN)63 Rome(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)70 Saigon(COLUMN)clear(COLUMN)8 p.m.(COLUMN)84 Sofia(COLUMN)pt. cldy.(COLUMN)2 p.m.(COLUMN)43 Stockholm(COLUMN)pt. cldy.(COLUMN)1 p.m.(COLUMN)46 Sydney(COLUMN)clear(COLUMN)10 p.m.(COLUMN)63 Tel Aviv(COLUMN)clear(COLUMN)2 p.m.(COLUMN)70 Tokyo(COLUMN)pt. cldy.(COLUMN)9 p.m.(COLUMN)70 Tunis(COLUMN)clear(COLUMN)1 p.m.(COLUMN)75 Vienna(COLUMN)rain(COLUMN)1 p.m.(COLUMN)55 Warsaw(COLUMN)rain(COLUMN)1 p.m.(COLUMN)46(END TABLE) Temperatures (Western Hemisphere)(TABLE) Cith(COLUMN)Weather(COLUMN)High(COLUMN)Low Acapulco(COLUMN)fair(COLUMN)91(COLUMN)78 Barbados(COLUMN)cloudy(COLUMN)82(COLUMN)73 Bermuda(COLUMN)fair(COLUMN)73(COLUMN)65 Bogota(COLUMN)cloudy(COLUMN)66(COLUMN)48 Cullacan(COLUMN)cloudy(COLUMN)95(COLUMN)63 Havana(COLUMN)pt. cldy(COLUMN)82(COLUMN)73 Kingston(COLUMN)cloudy(COLUMN)84(COLUMN)75 Montego Bay(COLUMN)fair(COLUMN)86(COLUMN)72 Mexico City(COLUMN)smoke(COLUMN)75(COLUMN)52 Monterrey(COLUMN)pt. cldy(COLUMN)82(COLUMN)61 Nassau(COLUMN)fair(COLUMN)82(COLUMN)73 St. Kitts(COLUMN)clear(COLUMN)84(COLUMN)74 St. Thomas(COLUMN)fair(COLUMN)84(COLUMN)73 Veracruz(COLUMN)cloudy(COLUMN)82(COLUMN)64(END TABLE)