You haven’t seen them for months, maybe even years, but that doesn’t mean you can let your guard down. They’re out there, waiting for the right moment to pounce. Just when you thought it was safe to go to the gas pump, they strike. That’s right: the 2018 summer driving season is gearing up, and crude oil prices are naturally rising in response. Get ready to crack that piggy bank, because this driving season looks to be one of the most expensive in years.

The daily national average for regular gasoline is currently sitting at $2.81 per gallon according to GasBuddy, and the price could keep climbing as we head into the busy summer months. That’s up from $2.39 a gallon last year, an increase of nearly 20% year-over-year.

Experts are conflicted on when gas prices will peak. AAA predicts that gas prices will continue rising over the next month heading into Memorial Day before stabilizing at that price point for the summer. But Patrick DeHaan of GasBuddy.com believes prices will continue to climb until mid-June.

Tom Kloza, global head of energy analysis for Oil Price Information Service told the Associated Press that “this will be the most expensive driving season since 2014.”

Have a road trip planned this summer? Make sure your fuel budget can handle it. While a slight increase in gas prices won’t be too detrimental to the economy in general, some families might really feel the sting as they take summer vacations. Nariman Behravesh, chief economist at IHS Markit, says that the increases will likely affect lower-income families as they see a larger share of their overall budget be consumed by gas:

Consumers as a whole will be hurt, mostly because gasoline prices are going up. At the higher income levels, this won’t really have much of an effect. But it’s a bigger deal for lower-income families, because a bigger share of their budgets goes to things like gasoline.

Average gas prices had been enjoying a downward trend for much of the year, but crude oil prices have reached three-year highs and continue to rise. That means gas prices aren’t too far behind and surprise, surprise – that increase is just in time for the peak summer driving season. 

According to a AAA estimate, 16% of gas stations in the U.S. are already selling gas for $3 a gallon and up.

Maybe it’s time to change that vacation into a staycation.