Perth has the most predictable cycle in Australia
Perth runs a weekly cycle, not a monthly one. Prices peak on Wednesday or Thursday and bottom out on Monday or Tuesday, week after week, with rare exceptions. The peak-to-trough swing is typically 20-30¢/L. If you fill up on the wrong day of the week in Perth, you're effectively paying a $15-25 weekly tax on a 60-litre tank.
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 pulls from the same feed, which means the prices on this page for tomorrow are not a forecast — they're a regulatory commitment. That makes Perth the easiest market in the country to time correctly.
How to play the weekly cycle
The simplest rule of thumb: fill up Monday morning or Tuesday evening, avoid Wednesday afternoon through Friday morning, and use FuelWatch's 24-hour advance prices to confirm the trough before it lands. If your tank can stretch past a Wednesday peak, you'll usually pick up a 15-25¢/L saving versus filling up at the peak. PetrolPulse's recommendation card above takes tomorrow's committed prices into account, so it can flip from "wait" to "fill now" the moment the cycle confirms.