Gas prices in Tennessee and across the country have jumped sharply in just the past few days, and the pain at the pump is not letting up anytime soon.

According to AAA data, Americans are now paying an average of 27 cents more per gallon than they were just last Sunday. The jump includes a 10-cent single-day spike that happened overnight from Monday into Tuesday, the biggest one-day increase since Russia’s invasion of Ukraine back in 2022.

As of Thursday, the national average for a gallon of regular gas sits at $3.25. That is about 36 cents higher than a month ago, and 15 cents more than this same time last year. Diesel is in even rougher shape. GasBuddy’s head of petroleum analysis, Patrick De Haan, reports the national diesel average has hit $4.12 per gallon, the highest price point since December 2023.

So what is driving all of this? A few things are happening at once.

The conflict in Iran sent crude oil futures spiking earlier this week. Brent crude, the international benchmark, climbed 3.8% to $84.52 per barrel on Thursday. That is a significant jump from the roughly $70 a barrel seen just late last week. On top of that, gas prices were already trending upward before U.S. and Israeli strikes on Iran, as refiners had already begun the seasonal switch to more expensive summer fuel blends.

The combined effect has been brutal in some states. A Nexstar analysis found that 23 states saw gas prices climb 15 cents or more since Tuesday alone. Kentucky and Arkansas led the nation in recent single-week increases, up 21 and 20 cents respectively. Since Sunday, at least 17 states have seen prices rise by 30 cents or more.

The states hit hardest this week include Georgia, where prices climbed 39 cents to $3.17 per gallon, Indiana at up 38 cents to $3.19, Florida up 35 cents to $3.24, Iowa up 35 cents to $2.99, and Ohio up 35 cents to $3.13.

The broader shift is visible nationwide. On Sunday, 39 states still had average prices below $3 a gallon. By Thursday, that number had dropped to just 17 states. Montana is teetering right at the edge at $2.996, with Iowa, Utah, and Wisconsin close behind.

De Haan pushed back on the idea that gas stations are cashing in on the spike. “Gas stations aren’t the villains during price spikes. They’re middlemen,” he wrote on X Thursday. “When wholesale prices surge, their costs jump immediately and margins often shrink while they try to keep up with higher replacement costs.”

At the center of the global supply concern is the Strait of Hormuz, a narrow chokepoint at the mouth of the Persian Gulf through which roughly one-fifth of the world’s oil travels. The ongoing conflict has effectively frozen tanker movement through the strait, which serves as the exit route for oil from Saudi Arabia, Iraq, Kuwait, Qatar, Bahrain, the UAE, and Iran itself. Most of that supply flows to Asia.

While Saudi Arabia and the UAE have pipeline alternatives that bypass the strait, the U.S. Energy Information Administration notes that most oil moving through the region has no other viable exit route.

President Donald Trump moved to address the disruption Tuesday, announcing on social media that he directed the U.S. International Development Finance Corporation to offer political risk insurance for tankers navigating the Persian Gulf at competitive rates. He also said the U.S. Navy would escort oil tankers through the Strait of Hormuz if needed. The Navy currently has at least eight destroyers and three littoral combat ships in the region, vessels that have previously been used for exactly this kind of escort mission in both the Persian Gulf and the Red Sea.

For now, drivers across Tennessee and the rest of the country should expect prices to remain volatile as the situation overseas continues to unfold.