Gas prices climb nearly 4 cents

(CNN) -- Prices at the pump are up nearly 4 cents in the past three weeks, continuing a trend of rising prices since mid-February, according to a survey published Sunday.

The national average for a gallon of gasoline is $2.85, Lundberg Survey found in the survey conducted April 9.

The rise in price coincides with a rise in crude oil prices in past three weeks. Crude prices rose the equivalent of 10 cents a gallon.

The trend points to a possible national average of $3, said survey publisher Trilby Lundberg.

The biggest factor as to whether gas prices will hit the $3 mark will be oil prices, she said.

"If it does (hit $3), it will be crude oil that does it, because gas demand continues to be very weak," Lundberg said.

While demand for gasoline typically increases in the summer months in the United States, high unemployment rates will keep demand down, she said.

The current average price of a gallon of self-serve is 80 cents above what is was a year ago, Lundberg said. The survey tallies prices at thousands of gas stations nationwide.

The city with the lowest average price in the latest survey was Newark, New Jersey, at $2.64. The highest was Honolulu, Hawaii, at $3.43.

Here are average prices in other cities:

Chicago, Illinois - $3.15

Portland, Oregon - $2.92

Portland, Maine - $2.88

Boston, Massachusetts - $2.80

Des Moines, Iowa - $2.79

Tucson, Arizona - $2.77

Atlanta, Georgia - $2.74

Salt Lake City, Utah - $3.01

Denver, Colorado - $2.68