Avoid These 3 Worst Days to Buy Gas

Gas prices may seem unpredictable, but data shows they follow a reliable weekly pattern. By simply adjusting when you fill up, you can sidestep common pricing spikes and avoid paying more than necessary.

A recent GasBuddy study confirmed that fuel costs can swing 30 to 50 cents per gallon within the same week. That’s a $5 to $10 difference per tank, depending on your vehicle — a meaningful savings over time for commuters, road-trippers, or anyone on a budget.

Here’s when not to fill up — and what to do instead.

1. Friday: Surge pricing kicks in

Friday is the most expensive day to fill your tank. Gas stations anticipate weekend travel and raise prices accordingly. Prices can jump 10 to 20 cents per gallon in many areas between Thursday morning and Friday afternoon, GasBuddy finds.

If you’re running low on gas, consider topping off just enough to get through the weekend, and plan your complete fill-up for midweek.

2. Saturday: Peak demand, peak prices

Saturday regularly sees the highest gas prices of the week. Weekend demand, unfamiliar routes, and limited station choices work against you.

If you must fill up, use apps like GasBuddy or Waze to compare local prices. A short detour could save several dollars per tank.

3. Sunday: Don’t expect a discount

While many drivers assume prices will drop by Sunday, that’s rarely true. Many stations maintain elevated pricing through Sunday night, anticipating the Monday morning rush.

If you’re low on fuel, buy the bare minimum to get through your commute, then refuel fully during the week.

So, when should you buy gas?

Tuesday is your best bet. GasBuddy consistently ranks Tuesday as the cheapest day of the week to buy gas. With weekend demand fading and stations adjusting prices, early Tuesday morning often delivers the best value.

Wednesday is a close second. Prices tend to remain low from Tuesday’s dip but start creeping upward by evening. If you miss Tuesday, try to fill it up before midday on Wednesday to stay ahead of the weekend climb.

Regular (non-holiday) Mondays also offer savings — just steer clear of holiday Mondays like Memorial Day or Labor Day. On those long weekends, stations often keep inflated prices through Monday evening due to ongoing travel demand.

Other ways to cut fuel costs

Timing your purchases is powerful, but it’s not the only trick. Combine smart fill-up habits with these strategies:

• Keep your tires properly inflated and use cruise control, when practical, to improve gas mileage.

• Shop with apps like GasBuddy, Waze, or Upside to find the best local prices.

• Consider warehouse club memberships (like Costco or Sam’s Club), where gas prices typically run 10 to 30 cents cheaper per gallon.

• When in doubt, don’t top off before weekends or holidays — buy just enough and wait for better midweek prices.

With just a little planning, you can save $10 to $15 a month — or as much as $200 per year — without changing how much you drive.