Perth Unleaded Resets to 249.9 at 57 Servos but the Rising Tuesday Floor Is the Bigger Story

If you drove past a BP, Caltex or 7-Eleven in Perth this morning, you probably saw the same number on the board. Of the 200 servos within about 16 kilometres of the CBD, 57 were asking exactly 249.9 cents a litre for unleaded at 2:00pm AEST on 23rd Sep 2026, which is noon in Perth. Yesterday the ones we track were sitting between 223.9 and 233.9.

So what happened overnight? Two separate forces are at work, and only one of them has anything to do with it being Wednesday.

Force one: the weekly cycle

Perth runs on a weekly price cycle, and the daily history for 79 metro servos shows it plainly. On each of the last three Wednesdays, the average jumped:

Think of it this way. Prices take the lift up and the stairs down. On reset day the big chains move their boards in one go, and the BP, Caltex and 7-Eleven sites in our sample went from an average of 228.9 yesterday to 248.6 today, a lift of 19.7 cents. Over the following days each servo shaves a few cents off to win customers from the one down the road, until margins get thin enough that someone leads the next reset. Economists call this an Edgeworth cycle, and it is why the best time to fill up in Perth keeps turning out to be Tuesday.

You might be wondering why so many rivals land on precisely 249.9. The number is a focal point. When sellers are all heading for roughly the same level, a price sitting just under a round figure is the natural place to stop, for the same reason a jumper is priced at $49.95 rather than $50.

Force two: the trend underneath

Compare Tuesday with Tuesday and the cycle drops out completely. What remains matters more for your budget: the Tuesday floor has gone from 199.9 to 210.9 to 227.0, a rise of 27.1 cents in a fortnight.

Independents such as Burk, Vibe, Atlas and Liberty averaged 195.9 on Tuesday 8th Sep and 224.0 yesterday, up 28.1 cents. The big three chains went from 200.1 to 228.9 on the same two Tuesdays, up 28.8 cents. The two groups price in completely different ways, yet their floors rose by almost the same amount. When that happens, the cause most likely sits further up the supply chain in wholesale costs rather than in anything decided at the pump.

So the cycle still tells you which day to buy, but the trend decides what you pay on that day.

Where the cheaper boards are today

The independents do not take the lift. They climb the stairs in both directions, a few cents at a time, which is why the gap inside some suburbs is so wide this afternoon:

Shell stations sit in the middle today. Their Reddy Express sites stepped up by around 7 cents to 235.9 and 240.9, a gentler move than the roughly 20 cent jumps elsewhere.

On a 50 litre tank, filling at 218.5 in Forrestfield instead of 249.9 saves $15.70. Our savings calculator will run the numbers for your own car.

Planning around next Tuesday

If the last two weeks are any guide, the big chains will start easing from Thursday while the independents keep inching up, and the two groups will meet somewhere in the middle before the next reset. That makes next Tuesday the likely low point again.

Just remember what the floor has been doing. A Tuesday price that is cheaper than today can still be dearer than last Tuesday, because the trend and the cycle are two different things moving at the same time. WA motorists have an advantage here: prices are locked for the whole day and FuelWatch publishes tomorrow's prices each afternoon, so you can see the next move before you commit to it.

You can follow daily moves across Western Australia on our unleaded petrol prices page. For the floor itself, take the longer view with our price trends.