Washington Gas Light Co. has reported a drop in profits from $14.2 million ($3.26 a share) in 1979 to $12.5 million ($2.87), figures that cover the 12-month period ending Feb. 29.

The company changed its accounting procedures recently and the decrease in profits reflectss that change, Washington Gas said. The accounting change alters the formula by which the company measures gas used by customers, but not paid for.

Directors of Washington Gas also declared a quarterly dividend of 63 cents a share, an increase of 3 cents over the previous dividend rate. The dividend is payable on May. 1.

The company said that without the change, the profits increased by 62 cents a share. The increase was due to higher retail rates and the selling of more gas to special contract customers.

But the company also said those factors were partially offset by the warm weather during the winter months.

Baltimore Gas & Electric Co. announced that profits for the two-month period ending Feb. 29 dropped from $21.5 million (69 cents) in 1979 to $14.9 million (47 cents) this year.

The company said the profits dropped because of higher supplier natural gas prices, increased operating costs and the moderate winter.