Metro Atlantans used to seeing gas prices under $2.30 a gallon over the past several months are doing double-takes this week when they pull up to the pump.

The average price for regular unleaded rose 4 cents a gallon overnight to $2.49 on Tuesday, according to GasBuddy.com’s most recent survey of prices across metro Atlanta.

Prices are up 11 cents since a week ago and 25 cents from a month ago.

Much of the increase can be traced to rising prices for crude oil, with refineries’ passing along the higher costs to retail customers and retailers’ passing along the cost to consumers. Despite an oversupply, crude oil prices are up more than 30 percent since March.

Gas also is more expensive due the switch to a more expensive summer blend, which helps fight air pollution as temperatures rise.

Metro Atlanta’s average price for regular unleaded was still lower Tuesday than the national average ($2.54), and still lower than the average metro price a year ago ($3.72).

The cheapest regular unleaded in metro Atlanta, according to GasBuddy’s survey, could be found at the following locations:

* $2.21 at a Pure station at E. Fairview Road SW and Union Church road in Stockbridge;

* $2.25 at a Valero at West Avenue SW and West Circle SW in Conyers.

* $2.28 at a Sam’s Club on Clairmont Road nearly I-85 in northeast Atlanta.