Days of the week on which average retail prices peak and trough
Chart S1 shows the days of the week on which prices peaked and troughed between January 2008 and April 2008. It provides a simple guide to the best days of the week, in general, on which to buy petrol.
Chart S1 Days of the week for peaks and troughs in prices for unleaded petrol in Sydney—January 2008 to April 2008
The chart shows the number (and percentage) of peaks and troughs for each day of the week between January 2008 and April 2008. It shows that:
the most common day for prices to peak was Thursday, with all 17 peaks
the most common day for prices to trough was Tuesday, with all 18 troughs.
Average retail prices over the past 30 days
Chart S2 shows average unleaded petrol prices in Sydney over the past 30 days until yesterday. This chart allows consumers to see where yesterday's average retail price falls in the current price cycle.
Chart S2
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Using this data, along with information about the length of price cycles over the previous four months (see chart S3 below), consumers can assess how long the current cycle may last and when may be the best time to buy petrol.
For instance, suppose chart S2 showed that the number of days between yesterday's price and the most recent trough was six days. Then suppose that chart S3 showed that the length of previous price cycles had generally been in the range of six to eight days. With this information, consumers could reasonably conclude that prices might increase in the near future.
On the other hand, suppose chart S2 showed that the number of days between yesterday's price and the most recent trough was only two days and that chart S3 showed that the length of previous price cycles had generally been in the range of six to eight days. With this information, consumers could reasonably conclude that prices might not increase in the immediate future.
However, while petrol price cycles often follow a general pattern they are not totally regular and therefore each cycle is likely to differ. Since historical data can only give an indication of what price cycles may do in the future, consumers should use this information as a guide only.
Length of price cycles
The chart below shows the number of days in each price cycle (i.e. from trough to trough) between January 2008 and April 2008.
Chart S3 Length of price cycles for unleaded petrol in Sydney—January 2008 to April 2008
The chart shows that :
the most common number of days in a price cycle was seven days, with all of the 17 cycles.
The ACCC permits interested parties to download information published on this site for the specified purpose of increasing community awareness about changes in petrol prices.
