Gas prices have reached a four-month high after surging all February in what may be a reaction to increased crude-oil prices at the end of last year, according to the latest report from the Energy Information Administration.

The average nationwide price for a gallon of regular gasoline is $3.75, up 21 cents from the first week of February and 45 cents from the start of 2013.

The EIA said that all states now have prices hovering above the $4 mark for the first time since October.

Prices began shooting up after Jan. 28, when the average price for regular was $3.36, and have yet to ebb, including double-digit weekly increases for two weeks in February.

December capped off a year of record-high average pump prices, but high crude-oil prices didn't trickle to the retail level until January and the first half of February, when the per-barrel price shot up $6, or 15 cents per gallon, according to the EIA. Refinery shutdowns for routine maintenance also drove up prices this month.

Increased production and additional imports should relax prices as the winter moves aside into spring, but for now, gas prices are indeed higher than we're used to seeing. Average regular prices in the Midwest shot up more than any region when compared with last week, at $3.76 per gallon. West Coast drivers saw an 11-cent increase from last week to $3.97 per gallon, while the East Coast took the smallest hit, up 10 cents to $3.75. Diesel, at $4.16 nationwide, is 20 cents higher than at the same time in 2012.

But don't bet on $4-plus summer prices just yet. In fact, with oil costs, it's good not to read too far into the future.

"U.S. refinery maintenance typically peaks in February, and we expect that many of the facilities that have recently decreased crude runs should return to normal operations in the coming weeks," the EIA said. "However, this increased supply will likely be countered by the seasonal increase in demand, which typically begins in the spring."

[Source: EIA]