Gas prices in Connecticut have climbed 21 cents in the past week and may inch up more as the summer driving season approaches, according to AAA.

A gallon of self-service regular in the state averaged $3.71 on Tuesday morning, up 21 cents from the week before and 29 cents from a month ago. The highest prices were reported in Windham County, lower Fairfield County and the greater Bridgeport area, the travel and auto club agency reported.

Part of the surge is due to the recent switch from "winter blend" gasoline — which makes it easier to start your car in cold weather — to the more pricey "summer blend," which causes less air pollution.

"The bottom line is that the summer blend fuel is designed to have lower emissions, but is more costly to produce," said Alec Slatky, managing director of public and government affairs for AAA Northeast.

Demand due to spring and summer travel also tends to boost gas prices, with a 20-cent jump seen last year around this time.

On the positive side, global oil prices have gone down in recent days due to developments in the Middle East, where a wider war between Israel and Iran appears to have been averted for now.

"We'll see where it goes, because hopefully, that will temper the price increases a little bit," Slatky said.

Regional gas inventories are also up, Slatky said, which could further help temper surges.

As of Monday, the average gas price nationwide was $3.67, up 4 cents from the week before and 14 cents from last month. Connecticut ranked 14th on AAA's list of states with the highest average gas prices, with California, at $5.43 a gallon, and Hawaii, at $4.78, topping the list.

This week's higher price is still far short of recent price records in the wake of Russia's invasion of Ukraine and inventory shortages in 2022 in the wake of the pandemic. According to AAA, the state's highest average price was $4.98 a gallon, recorded on June 14, 2022.