PORTLAND, Maine — Gas prices have risen in all three northern New England states over the past week.

GasBuddy’s daily survey of 1,228 gas stations in Maine found that prices rose about a penny to $3.11 per gallon on Monday. Prices in Vermont went up about 2 cents to $3.07 per gallon and prices in New Hampshire increased about a penny to $2.99 per gallon.

The price increases in New England mirrored a national increase in the price of gas, which went up a little less than a penny to $3.18 per gallon.

GasBuddy said in a statement that a decline in gasoline demand due to the end of the summer driving season means gas prices could decline in early fall.