Increases in the region's gas prices took a breather overnight: The averages were unchanged in the five-county region ($3.10) and in South Jersey ($2.91), according to AAA Mid-Atlantic.
The national average rose 1 cent overnight, to $2.97, the auto club said.
The average in Philadelphia and its four surrounding counties has gone up 19 cents in the last month; the increase over that span has been 18 cents in South Jersey and 12 cents in the nation overall.
The Mid-Atlantic region tends to have higher gas prices, a AAA spokeswoman said.
The average for diesel was unchanged overnight in the Philly area ($3.45) and in South Jersey ($3.11), but rose by 1 cent at the national level ($3.23).
Meanwhile, oil prices eased to around $88 a barrel as traders locked in profits after crude rose above $90 for the first time in more than two years.
At the early-afternoon mark in Europe, benchmark oil for January delivery was down 65 cents to $88.04 a barrel in electronic trading on the New York Mercantile Exchange.
The contract hit $90.76 on Tuesday, the highest price since Oct. 8, 2008 before pulling back to settle at $88.69, down 69 cents.
The pullback is not surprising, said Victor Shum, an energy analyst at consultancy Purvin & Gertz in Singapore. "It is primarily profit-taking after crude breached the $90 level in New York."
Some analysts now predict that oil will hit $100 per barrel sometime next year. They point to rising demand from China and other emerging economies. OPEC countries can crank up production to meet that demand now, but their ability to do that is expected to decline over the next few years.
Shum, however, said the $90 level wasn't sustainable for now amid persistent concerns about the spread of Europe's debt crisis to Portugal and Spain. This boosts the dollar and depresses the oil price as it makes the commodity more expensive for investors holding other currencies.
Fears that China may raise interest rates are also dampening the oil market, which is likely to trade between $85 and $90 in the near term, Shum said.
Traders will seek more clues on the strength of crude demand from U.S. government supply figures later Wednesday.
In other Nymex trading in January contracts, heating oil fell 1.47 cents to $2.4555 a gallon, gasoline futures gave up 2.34 cents to $2.2996 a gallon and natural gas rose 4.7 cents to $4.44 per 1,000 cubic feet.
In London, Brent crude was down 51 cents to $90.88 a barrel on the ICE Futures exchange.