Washington: Today - Mostly sunny and breezy, highs in mid to upper 50s, lows in mid to upper 30s. Chance of rain near zero today, 40 per cent tonight. Sunday - Rain, highs in mid to upper 40s.

Maryland: Today - Mostly sunny and breezy, highs in upper 40s to upper 50s, lows in upper 20s to mid 30s. Chance of rain in north and south tonight. Sunday - Rain in south, snow in north, highs in 30s to upper 40s.

Virginia: Today - partly cloudy, highs in mid 50s to mid 60s, lows in mid 30s to near 40. Rain is likely in southwest and possible elsewhere through commonwealth tonight. Sunday - Rain, highs in mid 40s to near 50.

Lower Potomac and Chesapeake Bay: Today - Clearing skies today, cloudy tonight with visibility greater than 5 miles through tonight. Winds should be northwesterly at 15 to 30 knots today becoming varible at 3 to 15 knots tonight.

Extended Area Outlook: For Monday through Wednesday - Partly cloudy skies with chance of precipitation Tuesday night and Wednesday. Highs should average in upper 40s and 50s, lows in upper 20s and 30s through the period. Washington's normal temperature range for this time of year is from 57 to 37.

West Virginia: Today - Cloudy, highs mid 40s to mid 50s, lows mid 20s to low 40s. Chance of rain in south today with rain likely in south and snow in north tonight. Sunday - Rain, highs in 40s.

ALMANAC DATA FOR Saturday, March 19: Sun rises 6:14 a.m., sets 6:19 p.m.; moon rises 5:58 a.m., sets 6:28 p.m. Tides: High 8:00 a.m. and 8:25 p.m., low 2:09 a.m. and 2:34 p.m. High and low tides at the following points can be obtained by subtracting the hours indicated from the tides above. Annapollis (3 1/4); Bloody Point Lighthouse (4 1/2); Deale, Md. (4 1/2); Colonial Beach (6); Norfolk (1 1/2); Virginia Beach (1); Solomon's Island (6 1/2); Point Lookout (7).

The Coucil of Governments' Air Quality Index for yesterday showed the high reading in the Washington area during the 2 to 3 p.m. period was 16 for the pollutant, photochemical oxidents. Index values between 0 and 24 Indicate good 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 remain about the same.

The National Weather Service forecasts that the Potomac River stage at Little Falls will remain near 5.3 or 5.4 feet through today.

Washington data at 7 p.m. (EST) yesterday: Highest temperature since 7 a.m. yesterday, 68 degrees at 1:40 p.m. Lowest temperature since midnight, 49 degrees at 2:40 a.m. Excess of temperature since March 1, 195 degrees. Deficiency of temperature since Jan 1, 62 degrees. Record high temperature for today, 85 degrees in 1945. Record low temperature for today, 12 degrees in 1876. Relative humidity: Maximum, 83 per cent at 8 a.m. Minimum, 41 per cent at midnight, 24 hour precipitation, 15 inches. Deficiency of precipitation since March 1,. 88 inches. Deficiency of precipitation since Jan. 1, 3.79 inches. Highest observed wind since 7 a.m. 22 miles per hour from the s.w. at 1:53 p.m. Peak gust since 7 a.m., 39 miles per hour from the s.w. at 12:46 p.m. Local Temp., Humidity(TABLE) Time(COLUMN)T.(COLUMN)H. 12 mid.(COLUMN)52(COLUMN)41 1 a.m.(COLUMN)51(COLUMN)48 2 a.m.(COLUMN)50(COLUMN)59 3 a.m.(COLUMN)50(COLUMN)77 4 a.m.(COLUMN)51(COLUMN)71 5 a.m.(COLUMN)51(COLUMN)69 6 a.m.(COLUMN)51(COLUMN)69 7 a.m.(COLUMN)50(COLUMN)80 8 a.m.(COLUMN)50(COLUMN)83 9 a.m.(COLUMN)51(COLUMN)80 10 a.m.(COLUMN)53(COLUMN)77 11 a.m.(COLUMN)54(COLUMN)69 12 noon(COLUMN)54(COLUMN)80 1 p.m.(COLUMN)60(COLUMN)75 2 p.m.(COLUMN)68(COLUMN)63 3 p.m.(COLUMN)62(COLUMN)78 4 p.m.(COLUMN)67(COLUMN)68 5 p.m.(COLUMN)68(COLUMN)57 6 p.m.(COLUMN)67(COLUMN)57(END TABLE)