Retail gasoline prices were up a penny on Friday to a national average of $3.831 per gallon, according to AAA, Wright Express and Oil Price Information Service.
The average price for a gallon of regular is now above $4 in Alaska, California, Connecticut, Hawaii, Illinois and New York.
Gasoline has jumped by almost 56 cents per gallon since Jan. 1 and is the highest ever for this time of year. That's costing drivers an extra $11.20 to fill up a 20-gallon tank. Experts are forecasting that the nationwide average could reach $4.25 by the end of April.
In Canada, the price averaged C$1.287 per litre, according to price-watching website GasBuddy.com, up from $1.237 a month ago.
For now, consumers aren't seeing similar increases in other areas. The U.S. Labour Department said Friday that excluding energy prices, inflation stayed mild in February. Food prices were unchanged for the first time in 19 months.
Yet there are signs that high gas prices are weighing on consumer confidence and the growth that fuels job creation. Economists fear consumers could cut spending on other goods, from appliances to furniture to electronics and vacations.
Gas prices are rising primarily because of high oil prices. On Friday oil markets were still reacting to reports a day earlier that the U.S. and the U.K. planned to release some of their strategic crude reserves. Although the White House denied the reports, independent analyst Andrew Lipow said traders were left to worry that Western nations are preparing for a prolonged standoff with Iran over its nuclear program.
"What do they know that they're not telling?" Lipow said.
Tensions with Iran, and the threat to oil supplies in the Middle East, are a big reason that oil has risen about seven per cent since Jan. 1 and almost 15 per cent since October.
In New York trading, benchmark oil for April delivery rose US$1.95, or about two per cent, to finish at $107.06, the biggest gain since Feb. 24. Brent crude for May delivery rose $3.21, or 2.6 per cent, to end at $125.81 per barrel on the ICE Futures exchange in London.
Natural gas, which is trading at prices not seen since 2002, rose 4.7 cents to finish at $2.326 per 1,000 cubic feet.
Heating oil rose 5.94 cents to end at $3.2819 per gallon and gasoline futures gained 6.84 cents to finish at $3.3569 per gallon.
Alex Kennedy in Singapore and Pablo Gorondi in Budapest contributed to this report.