Wholesale prices, which foreshadow prices consumers eventually must pay, rose 0.5 per cent in january, less than the 0.6 per cent rise in November and December, the Labor Department reported yesterday.

But most of the prices information was collected before the severe weather of late January and early February, which probably drove up food and other commodity prices.

The cold weather also apparently kept people away from stores as well. The Commerce Department reported that retail sales were $56.6 billion in January, 2 per cent below those in December. It was the first time they have fallen in four months.

A preliminary report for the first week in February shows a rebound in retail sales, however, which suggest that the sales lost because of bad weather will probably be made up, a government economist said.

A sharp slowdown in farm product price increases was the main reason that the rise in the overall wholesale price index decelerated, the Labor Department said.

Farm prices, which rose 2.6 per cent in December, rose 1.1 per cent in January. Prices for industrial commodities, such as machinery and metals, rose 0.5 per cent, after a modest 0.3 per cent rise in December.

Because the prices of industrial commodities fluctuate less than food prices, economists look more carefully at industrial prices as an overall indicator of inflation.

While industrial prices rose faster in January, their rate of increase was still much slower than in most months since Jan.

John Layng, chief price analyst for the Bureau of Labor Statistics, said that the wholesale price picture in early January was, on the balance, good.

But he cautioned that most of the wholesale price data were collected on Jan. 11, before the worst of the bad weather struck - tying up barge traffic and damaging many winter crops.

Furthermore, Layng said, natural gas prices are reported with a two-month delay, and many other fuels are reported a month late.

Nonetheless, the wholesale price of gas fuels was 32 per cent above that of a year ago, according to yesterday's Labor Department report, while refined petroleum products such as heating oil and gasoline were 5.9 per cent higher.

Price changes by themselves may not be good reflectors of the actual increases in costs faced by business or consumers. While gas prices are 32 per cent higher, gas consumption at home is up sharply because of the increased heating due to cold weather.

Total bills would reflect not only higher prices but increased consumption too. Industries that use natural gas normally have often had to switch to more expensive heating oil, or, in some cases had to shut down.

Government officials say they do not have good data on how many workers have been idled because of the weather. Estimates have ranged from 500,000 to 3 million.

Last week the Labor Department reported the unemployment rate in January fell from 7.8 per cent to 7.3 per cent, but cautioned that the survey was completed before most layoffs began.

The wholesale price and the unemployment reports suggest that the economy was improving steadily with no apparent acceleration in inflation until the middle of last month.

How much of a permanent impact the bad winter weather will have on the economy is unclear at this time. Carter officials have said that they think the impact will be temporary.

The Labor Department said its wholesale price index stood at 188 per cent of its 1967 average, which means that a collection of goods that cost $100 in 1967 cost $188 last month. The Labor Department adjusts all percentage changes for seasonal variation but does not adjust the index itself.

The department noted increases for vegetables and grains as well as coffee, hogs and poultry. Beef prices, which had been rising for five months, fell. There were also increases for textiles, apparel, machinery, paper, chemicals and durable household goods.