Perth has the most predictable cycle in Australia
Perth runs a weekly cycle, not a multi-week one — the ACCC puts the 2025 average at one week, against about five in Sydney and six and a half in Brisbane. Our own data puts the cheapest day on Tuesday and the dearest on Wednesday, with a day-of-week spread of roughly 15¢/L. That is six to thirty times larger than any other capital, and it makes the weekday the single most actionable signal in the product. Filling on Wednesday instead of Tuesday costs about $9 on a 60-litre tank, every week.
FuelWatch makes tomorrow's price public today
WA is the only state in Australia where retailers are legally required to commit to tomorrow's price by 2pm today, and then hold that price for a full 24 hours. The scheme is run by FuelWatch and has been in force since 2001. PetrolPulse ingests the same feed for today's prices. To see tomorrow's committed prices before they take effect, check FuelWatch directly — they are a regulatory commitment rather than a forecast, which makes Perth the easiest market in the country to time correctly.
How to play the weekly cycle
The simplest rule of thumb: fill up Tuesday, avoid Wednesday, and use FuelWatch's 24-hour advance prices to confirm the trough before it lands. On our measured day-of-week spread that is worth around 15¢/L versus filling at the weekly peak. The recommendation card above is built on the same weekly pattern — Perth is the one market where PetrolPulse treats the day of the week as the primary signal rather than a multi-week trough, because the weekly rhythm here is strong enough to beat the cycle model on its own.
Written and reviewed by Mark Schreuder, founder of PetrolPulse