Gas prices are rising in Montana as the state is greeted with warm, summer heat this first week of May.

"Right now, gas prices in Montana are rising, but only about four cents this past week. So you can expect to pay about $2.09," Petroleum Analyst Will Spear said. "That's still a discount, though, from what the rest of the United States averages at about $2.22."

Spear said crude prices are the main reason for the increase in gas at over $45 per barrel. Refineries are also working to continue their switch to the summer blend of gas.

"We're at the very end of spring as far as what the maintenence season is. Now that May 1 has past, we've switched over to the more expensive summer blend of gasoline," Spear said. "Refineries are scrambling to get their units back up to speed because summer time is when the big demand is."

Spear said Montana is up 10 cents compared to last month, and down 26 cents compared to this time last year.