Prices paid by Washington-area consumers rose 1.2 percent during the two months ended in May, with much of the increase attributable to higher gasoline and mass transit costs.

Nationally, prices rose 1.3 percent during the same period, the Bureau of Labor Statistics said yesterday.

The increase in the Washington area CPI was the first this year. During January and February, prices were stable. For the 12 months ended in May, prices rose a total of 5.1 percent.

Among the major factors in the price-index increase here were the 5-cent-per-gallon gasoline tax that took effect April 1 and the attendant increase in gasoline costs, and an April 16 increase in subway and bus fares.

Other factors included food and beverage costs, particularly the prices of fresh fruits and vegetables. Bad weather, which plagued produce-growing sections of the country during the spring, contributed to those higher prices, according to BLS economist Jesse Thomas.

Prices also were higher for beef and poultry, but somewhat lower for cola drinks, pork, fish, seafood and many dairy products.

During the two-month period, prices also increased slightly for housing, with home maintenance and repair charges leading this category. Those costs increased 2.5 percent.

Clothing prices rose 2.2 percent, with most of the increase occurring in the prices of women's and girls' apparel. Medical care costs rose .6 percent.

During the same two months, prices paid by Baltimore-area consumers rose 1.3 percent, the largest bimonthly advance for that area in 18 months.