Following a year of strong growth the index made for disappointing reading with prices dropping by 3.3% to an average price of £258,424.
This drop now sees an average property being marketed at almost £9,000 less than a comparable property was in November.
But the property portal expects the decline to be only a blip and predicts that asking prices are likely to rise by between 4% and 5% next year, a slight drop on the 7% in 2014.
Miles Shipside, Rightmove director and housing market, said: “Whilst a near £9,000 drop is the biggest ever reduction in the price of newly marketed property compared to the month before and a sign of a market continuing to cool, a fall is not unexpected in December.
“Though sellers are fewer in number at this time of year, those that do come to market are often keener to sell so price lower in a bid to stand out.
“The overall picture for the year is still one of a much recovered property market, with sellers and their estate agents confident enough to be putting property on the market at a higher price on average than a year ago, although we predict a slower pace of price growth in 2015.
“This means that sellers and agents will have to work harder to achieve a sale next year.”
Rightmove predicts the South East will see the highest growth in prices next year as the London ripple effect continues and stock shortages remain acute.
These factors mean that the East and South West regions also look set to perform better than the northern regions.
But it claims London will not be the price rise powerhouse leading the rest of the country as it has been in 2014 as it continues to re-adjust to the market changes seen in 2014.