The tumble in prices is relatively minor but a surprise even so, happening despite war in the Middle East, which has so far been contained to Israel and Gaza, despite fears of a much wider conflagration.
Mild weather and weak demand in countries such as America is being cited as being behind the drop in prices.
According to the Consumer Council NI, the average cost of buying 500 litres and 900 litres of oil has dropped to £370 and £657 respectively.
In late September 500 ltrs cost more than £400 and 900 ltrs more than £700. A year ago prices were higher still, at £460 for 500 ltrs and £814 for 900 ltrs.
After Easter this year oil prices fell dramatically, and stayed low from May to July.hovering around £290 for 500 ltrs and £500 for 900 ltrs.
David Blevings, of the NI Oil Federation, told the News Letter: “Oil prices are extending lower despite the continued conflict in Gaza. Prices are falling on weak economic data which is projecting weaker than normal growth and that affects overall oil demand.
"The milder weather has also impacted demand and we are now hearing that we could have a modest global supply/demand surplus in 2024. This is great news for consumers, but the caveat is that if the conflict in the Middle East continues and starts to extend into neighbouring countries and supply lines are compromised, we can expect prices to turn positive very quickly.”
Around 70% of homes in Northern Ireland use oil for heating, a higher percentage than any of the other countries in the UK, and more than the Republic of Ireland.