The best time to buy a used car in the UK is the month or so after the plate changes on 1 March and 1 September, when part-exchanged cars flood the market and prices soften.
The final days of March, June, September and December (when dealers chase quarterly targets) and December's deserted forecourts are the other genuine soft spots. And the right car still beats the right month, every time.
Why do used car prices drop after a plate change?
Because every new plate sets off an avalanche of part-exchanges. The Driver and Vehicle Licensing Agency (DVLA) issues a new age identifier on 1 March and 1 September each year, and buyers who want the newest number collect their cars at once.
The Society of Motor Manufacturers and Traders (SMMT) counted 380,627 new cars registered in March 2026, typically the busiest month of the year. Nearly every handover leaves a used car behind, the same maths that explains why part-exchange offers run below market.
All that stock lands on forecourts over the following weeks, priced to move. Auto Trader's Retail Price Index has September typically down around 0.6% month-on-month since tracking began in 2011, a small average hiding deeper cuts on the models dealers suddenly have three of.
What's the cheapest month to buy a used car?
March–April and September–October are the strong windows, with December a quieter third. Here's the whole year, honestly graded:
| Month | What happens in the market | Buying opportunity |
|---|---|---|
| January | New-year buyers return; December's deals evaporate | Weak |
| February | Lull before the March plate; dealers hold stock back | Moderate |
| March | Plate change: part-exchanges pour in while showrooms deliver new cars | Strong |
| April | The March glut sits on forecourts, priced to shift | Strong |
| May | Glut digested; prices firm back up | Weak |
| June | Quarter-end targets loom in the final week | Moderate |
| July | Summer lull: convertible prices peak, 4x4s go unloved | Moderate |
| August | Buyers hold off for the new plate; motivated sellers deal | Moderate |
| September | Plate change and quarter-end together: supply floods in | Strong |
| October | September's trade-ins hit the market, keenly priced | Strong |
| November | Demand cools ahead of Christmas; stock still plentiful | Moderate |
| December | Footfall collapses; year-end targets meet empty showrooms | Strong |
Is the end of the month a good time to buy a car?
Yes, and the end of a quarter is better. Dealers and their sales staff work to monthly and quarterly targets, and a manufacturer or group volume bonus can be worth more than the margin on the single car that hits it. The last few days of March, June, September and December are when a marginal deal gets nodded through.
You can't see a dealer's targets from the outside, so treat the calendar as a tailwind rather than a coupon. Make a fair, researched offer and let the date do the leaning. Private sellers have no targets, but a December advert gets few calls, and a seller three weeks into silence listens hard to the one buyer who turns up.
When are convertibles and 4x4s cheapest?
Convertibles are cheapest in the depths of winter and 4x4s in high summer, because demand is seasonal and the stock has to sit somewhere. Nobody test-drives a soft-top in January drizzle, so January soft-tops are priced for the patient; by the first warm bank holiday the same car costs noticeably more.
Four-wheel drives run the opposite cycle: unloved in July, repriced at the first snow forecast, when everyone remembers they live up a hill. Buy your summer car in November and let it hibernate: buying against the season is the one timing trick that works nearly every year.
When is the best time to buy a used electric car?
EV timing is less about the calendar and more about supply. Auto Trader's index put the average used EV at £23,678 in January 2026, down 7.2% on the year, with a third more stock as the first big wave of leases matured. Demand rose too, and used EVs were still the fastest-selling fuel type on that data, so the extra supply is softening prices rather than stranding cars on forecourts.
While that holds, a used EV is one of the few cars where patience keeps being rewarded in any month; the checks in our used EV guide matter more than the date on the calendar.
Does the right month matter more than the right car?
No: a good car in a bad month beats a bad car in a good month, every time. Saving a few hundred pounds by shopping in the glut and then picking the example with a murky past is a terrible trade.
The part-exchange wave also changes what's on sale: ex-fleet and ex-lease cars pour in (some superb, some traded a step ahead of an expensive bill), many moving through trade auctions and onto forecourts within weeks.
So the busy weeks are when checking matters most, not least. Read the service history properly, and run the reg before you travel: a £5 report puts the MOT history, full mileage trail, tax status and spec on one page, which is cheap insurance against a glut-priced mistake.