The national average price of regular unleaded remained flat as the summer driving season draws to a close, according to federal data and AAA data.

The average price fell one-tenth of a cent to $2.149 for the week ending Aug. 15, according to the U.S. Energy Information Administration. AAA data showed the average price reaching $2.12, after declining for 54 of the prior 55 days.

"With gasoline supplies high and oil prices still relatively low, pump prices are likely to remain cheap through the rest of the summer and into the fall and could even dip back below $2 per gallon once the summer driving season is complete," according to a AAA release. "However, a major market-moving event, like a hurricane or increasing crude oil costs, is not out of the question and could still offset this decline and temporarily drive pump prices higher."

In recent weeks, the Midwest region has shown the most price volatility. This week, the average price increased six-tenths of a cent to $2.121. The sharpest declines came on the West Coast with a 3.9-cent decline to $2.534. The West Coast without California fell 4 cents to $2.347, according to federal data.