Consumer prices rose by 0.4 percent after seasonal adjustment in July, bringing the overall increase in prices over the past year to just 2.4 percent, the lowest annual rise since 1966, the government reported yesterday.

However, many analysts expect an uptick in the inflation rate later this year. Declining food prices were partially responsible for the moderate price increase in July, the Bureau of Labor Statistics said, but the severe drought across the nation will likely push up food prices later this year.

So far, the drought has led to cheaper meat prices, with the slaughter of livestock increasing because of the shortage of grain and rapidly rising prices of animal feed. In July, prices of beef and pork dropped sharply, and the average cost of meat, fish, eggs and poultry was down by 0.9 percent, yesterday's report said.

But meat prices will rebound later this year when fewer animals are available for slaughter. Grain prices will also rise because of the expected poor harvest, analysts say.

In the first seven months of this year, consumer prices climbed at an annualized rate of 3.2 percent, compared with an increase of 3.9 percent during 1982. Most economists predict that the overall inflation rate for 1983 will be between 4 percent and 5 percent.

This would still represent a sharp slowdown from the double-digit inflation rates experienced in 1979 and 1980. The recession since then dealt a significant blow to inflation, and most economists forecast continued relatively slow rates of inflation for some time. However, the pace of the economic recovery, together with above-target growth in some measures of the money supply, have led to fears among some economists that inflation may start back up again.

The consumer price index, before seasonal adjustment, stood at 299.3 in July (1967 equals 100). This means that a basket of goods costing $100 in 1967 would have cost $299.30 last month.

A companion price index, the Consumer Price Index for urban wage earners and clerical workers, rose by 0.3 percent last month, before seasonal adjustment, to 298.2 (1967 equals 100). This index is widely used to calculate cost-of-living increases in wage contracts and government benefit programs.

The July rise in consumer prices was twice as large as the 0.2 percent monthly increase recorded in June, when food prices dropped by 0.3 percent. In July, food costs were down by 0.1 percent.

Aside from that category, there were slight price increases across the board last month. Gasoline prices rose by 0.4 percent after a 0.7 percent increase in June and substantially larger increases in April and May, the Labor Department said. Used-car prices jumped by 1.5 percent, but new-car prices were unchanged from June.

Most of the "major expenditure categories recorded moderate increases in July, except for the other goods and services index, which registered a large gain," the Labor report said. This category climbed by 1.3 percent between June and July, largely because of a steep 3.3 percent rise in cigarette prices. Over the past 12 months, cigarette prices have risen by 25 percent, the Labor report said.

Medical costs, which were 8.4 percent higher last month than a year earlier, rose by 0.6 percent in July. This was "somewhat more than the increases in each of the previous four months, though significantly less than the double-digit rates that prevailed during the past four years," the Labor Department said.