Coming at the close of an erratic year when consumer confidence and retail sales have been hard to predict and as a recession and unemployment in several sectors begin to take a toll, the advent of the Christmas season has major Washington area retailers more than a little jumpy.

The semiofficial description of this mood is "cautious optimism."

"I predict optimism in the air," said Leonard Kolodny, director of the retail bureau of the Greater Washington Board of Trade. "The merchants are complaining about the fact that sales are a little spotty, but they look forward to holiday sales with cautious optimism," said Kolodny, whose outlook generally is not pessimistic.

"I'm always optimistic," said Woodward and Lothrop President David Mullen. "I'm cautiously optimistic, but we're certainly not going to step out with a lot of extra merchandise. We're playing it close."

"I think it's going to be tough," said William Detwiler, chairman and chief executive officer of Garfinckel's. "The last four weeks have been disappointing, and there is an economic problem here in the Washington area. We just think it's going to be a tough season."

While others may complain about rushing the Christmas season, retailers have no choice but to plan for it now. A part of the Christmas ordering was done last summer. What consumers are buying now and how fast will determine additional Christmas orders.

It is not a season that retailers take lightly since it accounts for approximately 40 percent of the year's earnings.

Nationally, the outlook is sobering for retailers. Commerce Department figures for September sales showed a slowdown. "Santa Claus is going to come but he's not going to have a big bag," said Terrence McEvoy, a retail analyst for Dean Witter Reynolds. Nationally, "retailers are very conservative," he said. "They're keeping inventories and expenses under control."

Usually, Washington area retailing floats serenely above economic storms that affect the rest of the country. "They've tended to weather those storms a little better largely because of the nature of the Washington area economy," said William L. Paternotte, an analyst for Alex. Brown in Baltimore.

This year the Washington area is beset by higher unemployment -- and a different unemployment from what one would ordinarily expect here. This year's job hunters include axed government workers, former Washington Star employes, laid-off consultants and others from the solid middle- and upper-middle-income ranks of shoppers.

"It's probably one of the highest unemployment rates I can remember. It has to be a factor," Mullen said. "It's not just the people who are unemployed in the government." What's happening also affects those who are still working, he said. "It's the uncertainty."

"This has not been a sparkling year in terms of retail sales, but it is not dull," Kolodny said. "There have been a couple of weeks when there have been dips, but generally they're holding their own." Suburban sales have, as usual, been stronger than sales in the city. The board of trade doesn't release its figures, however.

Detwiler of Garfinckel's, who said he has a fix on what is happening generally through the board of trade reports, said they "do not indicate it's a disaster, but it's not typical for Washington."

The outlook for the Washington area is not so much dismal as it is simply unpredictable.

Some of the variables include the weather, interest rates, consumer confidence and to what extent consumers opt to put their money into All Savers accounts or other savings instruments rather than Christmas presents. According to Kolodny, the news will also have an impact.

"It seems to me that shoppers are ready to let loose and go out to the stores in droves in the holiday season," he said. "The reason they're not doing it is because some of the derogatory publicity that comes through," he said. Kolodny was speaking of such news reports as stories about area unemployment and stories quoting President Reagan as saying the country is in a recesssion.

Some retailers say they are actively, rather than cautiously, optimistic about Christmas sales. "We feel very positively about our fourth quarter," said Edward Mangifico, president of Hecht's, where the Christmas theme will be "make someone happy."

"We're more optimistic this year than last year," said Fred Bell, senior vice president of W. Bell & Co. "I don't know whether things have gotten better or whether people have just gotten used to it. There's a limit to how long people will wait to get the things they need," he said. The signs so far point to a Christmas season that is an improvement over Christmas past, he said.

Scott Goode, president and owner of Lowen's, a toy store in Bethesda, is "fairly optimistic." "I know a lot of people are concerned with layoffs and tight money, but business for us so far has been tremendous. It's been increasing significantly over the last couple of years, and I expect it will through Christmas. People seem to be in a buying mood."

Earlier this fall, the Lowen's annual pre-season sale in which all goods are discounted 20 percent ran almost 30 percent ahead of last year's sales. While some of that increase reflects a bargain-hunting approach to Christmas, Goode said the sale is almost always an accurate indication of how the Christmas season will go. "We're in our 14th year."

Retailers continue to report that shoppers seek out somewhat higher priced, more durable goods. "Someone will buy a $100 set of blocks because they know it will last for three or four kids instead of buying a piece of junk for $8 or $9," Goode said.

Shoppers also look for metallic apparel and other items that proclaim their newness and accessories that achieve a new look for relatively little money, retailers said.