Winter's approach spells bargain time for used car buyers, according to a new survey of used car dealers.

It reveals November and December as two key months for snapping up high-quality cars at knock-down prices.

Researchers for CAP Black Book -- the confidential industry benchmark used car trade values guide -- surveyed a regionally-weighted and representative sample of dealers to measure retail demand throughout the year.

Their findings revealed that retail demand grinds almost to a halt towards the back-end of the year.

The survey reveals that just as retail demand reduces the market receives additional supply from September registrations made over previous years, returning from contract hire, leasing and daily rental fleets -- meaning more choice for the consumer.

Dealers were questioned on their best used car retail sales times of the year, revealing a clear profile for retail used car demand over the course of 12 months. The strongest demand is revealed to come in March, with a surge in retail sales compared with the start of the year.

Sales then continue strongly on a slow downward trend throughout the summer before peaking again in September.

CAP Black Book managing editor, Daren Wiseman, said: "Used car retailers have long been familiar with the end-of-year lull but this survey graphically reveals just how little retail activity there is.

"This represents a great opportunity for used car buyers because dealers will work harder than ever to win every sale when genuine potential customers are such a rare sight."