With the unpredictability of a dazed boxer, Washington's weather lurched through the area in 1984, delivering spring in December, summer in October, cloudbursts in March and a soggy, mildewy mess in July that defied seasonal definition.

But when you add up all the crazy meteorological numbers and divide by the 12 months of the year, the average turns out to be breathtakingly normal.

According to unofficial year-end figures, the average temperature for 1984 was 57.8 degrees, only 0.3 degrees above normal. Total precipitation came to 37.73 inches, little more than an inch below normal.

Throughout much of the year, however, the weather took freakish swings, shattering three temperature records, tying four others and threatening still others. Just in the last two weeks of springlike conditions -- who could forget them? -- soaring temperatures broke or matched longstanding records on three days in December, including Dec. 29, when the thermometer climbed to 75 degrees, tying the warmest day ever recorded in a December here. The previous record was set on Dec. 28, 1946.

December as a whole averaged 45.6 degrees, also tying the warmest December on record set in 1889.

There were other warm spots during the year as well, but few of them in the summer. The official National Weather Service thermometer at Washington National Airport measured 71 degrees on Feb. 24, erasing the old record of 70 degrees set for the date in 1975. The entire month of October, with several days in the 80s, turned out to be the warmest since the weather service began keeping records here in 1871. It averaged 65.2 degrees, 0.5 degrees warmer than the old record set in 1971.

Though no cold records were set during the year, there were some close calls. On Jan. 20, 21, and 22, the thermometer tumbled to lows of 9, 8, and 3 degrees, respectively, coming within a degree or two of records dating to the late 19th century.

The unseasonably cool weather was reserved for the so-called summer of 1984. While much of June was hot and muggy in true Washington form, July and August were just muggy. July, with an average temperature of 76.5 degrees, was the coolest in 22 years. July and August recorded only four days each with readings in the 90-degree range, far below the average of 24 days in that range. The temperature fell to a chilly 58 degrees on July 8, only four degrees above the record low for the date set in 1892. The thermometer never got above 91 in August.

July was a gloomy, besodden month. A little more than four inches of rain fell during the month, not spectacular in itself, but it was spread out evenly, spoiling weekend trips and lunchtime strolls for everyone. All told, rain fell on 17 days. Thirteen days were classified by the weather service as cloudy, 16 as partly cloudy and only two as clear.

March turned out to be the wettest month of 1984, with 6.14 inches of rain, snow, sleet and other wintry yuck slushing up the streets, snarling traffic and wreaking general havoc. It was the wettest March since 1953, when 7.43 inches fell.

Snow was not the problem it has been. While more than 20 inches of snow plagued the city in three of the last four years, only 8.6 inches fell in 1984, most of it in January. Snowfall varies wildly in Washington, with annual totals ranging from as little as an inch in 1931 and 1.6 inches in 1913, to 35 inches in 1979 and almost 50 inches in 1899.

While the year's total precipitation of 37.73 inches was close to normal, it left the Potomac River flowing generally well above normal levels, ensuring more than adequate supplies for municipal use. The average flow of the river was 11 billion gallons a day, almost double the long-term average of 5.9 billion gallons a day, according to the U.S. Geological Survey, which clocks the river at Little Falls.

"It was certainly a wet year for us . . . . It was a good year," said survey spokesman Don Findley.

The river reached its highest daily level on Feb. 16, at 135 billion gallons, and its lowest on Oct. 18, at 1.8 billion gallons, Findley said. Daily diversions of water from the river by the District of Columbia and the Washington Suburban Sanitary Commission ranged from a low of 261 million gallons on Jan. 26, to a high of 446 million gallons on June 13 during what amounted to the year's only hot spell.