The UK's twin plate-change peaks: why March and September dominate registrations
The United Kingdom is the only major market with two plate-change peaks in a single year. In 2025, March alone delivered 357,103 new-car registrations (18.4% of the full year) and September delivered 312,891 (16.1%). Combined, the two plate-change months represent roughly 35% of UK passenger-car sales — a concentration similar in magnitude to Ireland's January spike, but split across two windows.
UK monthly share — 2024 vs 2025
| Month | 2024 share | 2025 share |
|---|---|---|
| January | 4.9% | 5.1% |
| February | 4.6% | 4.7% |
| March | 17.9% | 18.4% |
| April | 7.0% | 7.1% |
| May | 7.5% | 7.4% |
| June | 9.4% | 9.2% |
| July | 7.3% | 7.1% |
| August | 4.5% | 4.6% |
| September | 16.4% | 16.1% |
| October | 7.5% | 7.4% |
| November | 7.1% | 7.0% |
| December | 5.9% | 5.9% |
The plate-format mechanics
Britain's number plate carries a two-digit "age identifier". The March plate runs 25 in 2025, while the September plate flips to 75. Buyers wait for the plate change to maximise the perceived "newness" of the car, especially for company-car and lease buyers whose monthly cost reflects residual value at trade-in. The pattern has held since the current format launched in 2001.
Implications for the market
Two effects matter for anyone forecasting UK demand:
- Demand pull-forward and pull-back. February and August are statistically the weakest months of the year because deferred demand pulls toward March / September. A weak February is not a market signal — it's a calendar effect.
- EV-share volatility. Plate-change months magnify whatever powertrain mix the dealer network is pushing. The September 2025 plate window saw BEV share jump to 24.1% — the highest for any single UK month on record — reflecting both ZEV-mandate compliance pricing and inventory clearance.
Source & methodology
Monthly shares verified against SMMT (Society of Motor Manufacturers and Traders), the official UK new-car registration source. Light commercials and used-car sales are excluded; passenger cars only. The full 2015–2026 monthly series is available on the UK dashboard with brand and powertrain filters.