The nation's major retailers, aided by sales of "big-ticket" items and traditional promotional activities, yesterday reported higher sales in February despite heavy snow and rainstorms around the country.

The February gains came on the heels of strong sales increases in January and provided analysts with encouraging evidence the consumer is finally beginning to spend again in sufficient volume to help spur economic recovery.

"The recent reduction in interest rates and unemployment, coupled with lower inflation and growing consumer confidence, will gradually improve the economic picture for 1983," said Jeffrey Feiner, retail analyst at Merrill Lynch, Pierce Fenner & Smith.

Sears, Roebuck & Co., the nation's largest retailer, said its sales climbed 4.3 percent from February 1982. K mart Corp., ranked second, reported an 8.6 percent gain in the first month of the industry's new fiscal year. F. W. Woolworth Co., the fourth-largest retailer, said its sales grew 1.8 percent.

Of the top eight retailers, only third-ranked J. C. Penney & Co. reported a decline, saying sales for the four-week period slipped 1.4 percent.

Feiner said the improvements came "despite the adverse impact of unseasonable weather in various parts of the country during February, most notably the snowstorm in the Northeast in the midpart of the month, but also the heavy rains on the West Coast at the end of February."

Analyst Jeffrey Edelman at Dean Witter Reynolds Inc. said durable goods--big-ticket items designed to last three years or longer--showed a larger rebound in February than other merchandise.

Sears, based in Chicago, said its four-week sales increased to $1.27 billion from $1.22 billion.

Troy, Mich.-based K mart said its sales jumped to $996 million from $917.4 million. Penney, based in New York, said sales for the month totaled $567 million compared with $575 million. Woolworth, also based in New York, said its four-week sales amounted to $304.8 million against $299.3 million.