Retail sales were lackluster last month in the face of severe weather and a general downturn in the economy, the nation's leading retailers indicated yesterday.

Major department and specialty store chains reported mixed sales results, but even those that showed increases for the month netted only marginal gains, for the most part.

In metropolitan Washington, officials at major regional and national chain stores described last month's sales as disappointing. Local retailers as a rule don't report monthly sales, but their assessments of January's results mirrored the national picture.

"I don't know anybody that had a good January," said Edwin K. Hoffman, chairman of Washington-based Woodward & Lothrop. "The whole town had a bad month. Between the snow and ice and the plane crash, we never had a chance."

"As we were expecting back in the holiday season, January turned out to be quite lackluster," said William Striegl, district manager for the 11 J. C. Penney Co. Inc. stores in the Washington-Baltimore market.

"It was a very disappointing month," said William Detwiler, chairman of Washington-based Garfinckel's, a specialty-store division of Allied Stores.

Severe weather snarled traffic and forced shoppers to stay home, causing several area merchants to close early at least twice last month.

Ironically, those conditions produced robust sales in some product lines at Hechinger Co. stores. Richard England, chairman of the Landover-based do-it-yourself chain, said sales of snow-removal products and insulation materials set records.

On the other hand, "Sales were very poor in categories that don't relate to weather," England said.

Nonetheless, "I'm not blue about that, because I can't control the weather," he added. "I worry about what I can control."

Domestic merchandising sales of the nation's largest retailer, Sears, Roebuck & Co., increased 6.1 percent to $1.19 billion in January from $1.12 billion in the comparable month last year.

No. 2 K mart Corp. reported slightly higher sales for the four-week period as volume climbed to $981 million from $836.9 million a year earlier. For the fiscal year ended Jan. 27, sales were $16.53 billion compared with $14.2 billion, up 16.4 percent.

Penney reported a 0.6 percent sales decline for January as volume fell from $648 million a year earlier to $644 million. For the final quarter, sales rose to $3.8 million, a gain of 3.3 percent. For the 52 weeks ended Jan. 30, volume advanced 6 percent to $11.9 million from $11.19 million.

May Department Stores Co., parent of D.C.-based Hecht Co., said preliminary sales figures for January show a marginal gain of 1.6 percent as volume increased from $170.7 million to $173.4 million.

Federated Department Stores Inc., whose stores include Bloomingdale's, recorded a 6.6 percent sales increase in January. Sales totaled $412 million compared with $386.7 million a year earlier.

Carter Hawley Hale Stores Inc., parent of Neiman-Marcus, compiled $165.7 million in sales last month, an increase of 6.1 percent over the $156.2 million for January 1981.

Montgomery Ward & Co. saw net sales fall 10.1 percent from $332.6 million in January 1981 to $299 million for the four-week period ending Jan. 20, 1982.