What you pay for the heating oil that gets piped into your storage tanks, the local heating oil prices, are influenced by a number of factors - some truly local, and others that are really international.
The truth is that folk with oil fueled home heating furnaces are subject to the whims and production choices of OPEC nations. (OPEC stands for Organization of Petroleum Exporting Countries.) This is because something in the region of forty percent of the cost of home oil comes from the cost of a crude barrel. Not much you can do about that unless you happen to have an empty storage tank when you read in the financial section that oil has hit a ten-year low!
The price you fork out to keep your oil fired home boilers running is also influenced by local competition. If you live in an area where there is not much (or any) choice of supplier then there is little incentive for the supplier to set prices as low as they can manage. Of course the supplier in remote areas also has justifiable additional delivery expenses over some other suppliers.
Your oil prices are also influenced by the stockpile that the refinery has accumulated. Since crude oil is made into several products simultaneously, the refineries aim to manage the seasonal products (like heating oil) as best they can given that the also need to make non-seasonal products with the same oil.
These are the three main factors that influence the price paid for heating oil. It explains why it is smart to buy out of season (low demand), but in the end you have to buy when your tank is empty, so you will have to pay the market rate.