The short answer
Yes, a little, and mostly not for the reason people think. Pooling every class 4 first test from 2021 to 2025, the national pass rate was 70.0% in January, 70.2% in November and 70.5% in October, against 72.5% in March and 72.6% in September. That looks like a winter dip.
Most of it is who gets tested when. March and September are the plate-change months, so three years on they are crowded with cars at their first MOT, which pass far more often than old cars. There were 3,947,885 first tests on cars aged 3 to 5 in March and 2,138,330 in December. Compare months within one age band and the dip shrinks to a fraction of the headline gap, and the record cannot say whether even that is the weather. For most drivers the message is the reverse of the myth: your car's age matters far more than the month.
Pass rate by month, all ages and two age bands
First-test pass rate by calendar month, 2021 to 2025 pooled. Age is the test year minus the year the car was first used.
| Month | All ages | 3 to 5 years | 15 years and over |
|---|---|---|---|
| January | 70.0% | 86.5% | 56.0% |
| February | 71.0% | 86.6% | 56.4% |
| March | 72.5% | 86.4% | 57.4% |
| April | 71.2% | 85.5% | 57.6% |
| May | 72.2% | 85.8% | 58.6% |
| June | 72.5% | 85.8% | 58.7% |
| July | 71.6% | 85.8% | 58.5% |
| August | 71.6% | 86.2% | 58.6% |
| September | 72.6% | 86.4% | 58.3% |
| October | 70.5% | 85.8% | 57.4% |
| November | 70.2% | 85.7% | 57.1% |
| December | 71.2% | 85.9% | 58.3% |
Within the 3 to 5 band the months run from 85.5% in April to 86.6% in February. Within 15 and over, the band that moves most, from 56.0% in January to 58.7% in June. The 6 to 9 band runs from 76.1% in November to 77.9% in March. In every band the gap between the highest and lowest month is small next to the gap between bands: in October a car aged 3 to 5 passed 85.8% of tests, a car aged 15 or more 57.4%.
Why the headline line misleads
The all-ages figure is an average of very different groups, and the mix changes every month. Months full of young cars score high, not because any car did better but because the mix got younger. Quiet months like December and January tilt the other way. That is why the honest comparison is within an age band, and why this article does not hang a weather story on the small within-band differences. The record has test dates but nothing on why a car failed in a given month beyond the defect itself; a fault found in January may have been there since August. Cold, dark and wet months may make some faults more likely. The figures cannot prove it, and we do not claim it.
What a winter fail costs, and how to limit it
The maximum fee for a car MOT is £54.85, set on GOV.UK. A car left at the test centre for repair is retested free within 10 working days under the GOV.UK retest rules. A car taken away and brought back before the end of the next working day is retested free for a list of items that includes lamps other than headlamp aim, wipers and washers, wheels and tyres, mirrors and number plates. For anything else brought back within 10 working days a partial retest fee can be charged; after that it is a full test again.
Several winter items are on that free list, so check them yourself the week before. You can also go early: GOV.UK says you can get an MOT up to a month, minus a day, before it runs out and keep the same renewal date, which leaves time to fix a fail before the old certificate expires. The MOT history service shows when it ends and what was recorded last time.
- All lights, including number plate and brake lights.
- Wiper blades and both washer jets, bottle full of screen wash.
- Tyre tread and pressures, including the inner shoulders.
- Dashboard warning lamps that stay lit.
- Horn, mirrors, plates clean and legible.
- Last year's minor items and advisories, a year older now.
What this does not mean
It does not mean booking in March helps your car pass; March scores high because of which cars are tested then. It does not mean a winter test is unfair or that a winter fail would have been a summer pass. And it does not mean weather has no effect; it means this record cannot measure one. For context, the national pass rate for the whole of 2025 was 72.3%.
Frequently asked questions
Slightly, on the headline figure: 70.0% of first tests passed in January against 72.6% in September, pooling 2021 to 2025. Most of the gap is the age mix of cars tested each month. Within one age band the difference is much smaller, and the record cannot attribute it to weather.
September for all ages together, at 72.6%, with March and June at 72.5%. Both plate-change months are full of cars at their first MOT. Within 15 and over the highest month is June at 58.7%.
Booking early does not change how your car tests, but it buys time. GOV.UK says you can take the MOT up to a month, minus a day, before it runs out and keep the same renewal date, so a fail can be fixed before the old certificate expires.
The maximum fee for a car is £54.85. A retest is free if the car is left at the centre and retested within 10 working days, or brought back before the end of the next working day for certain listed items; otherwise a partial retest fee can be charged within 10 working days, and the full fee after that.
Sources and method
Pass rates are passes divided by class 4 first tests, with pass after rectification counted as a fail, by calendar month of the test, for all ages and for the 3-5, 6-9, 10-14 and 15-and-over age bands, test years 2021-2025 pooled (14,617,336 first tests in January to 16,264,949 in September, all ages). National figures have no group floor.
- DVSA anonymised MOT results, class 4 first tests, 2021-2025 (data.gov.uk)
- GOV.UK: MOT test fees
- GOV.UK: MOT retests after a repair
- GOV.UK: When to get an MOT
- GOV.UK: Check the MOT history of a vehicle
About these figures. Figures are computed by SortedCars from the DVSA anonymised MOT results dataset (class 4, first tests only, test years 2021-2025), published under the Open Government Licence v3.0. Pass rate = passes divided by first tests, with pass-after-rectification counted as a fail. No figure is shown for any group with fewer than 500 tests. Test class 4 only, first tests only; retests are excluded. Pass rates describe fleets, not individual machines: they reflect how cars were driven, maintained and used as well as how they were built, and beyond recorded mileage none of that is in the data. A well-kept example of a model with a weak average can still pass; a neglected example of a strong one can still fail. Alias spellings of a make are counted under one make name and all trims of a model under one model name, using SortedCars' grouping tables.
This article is general information drawn from published test records. It is not professional, mechanical or legal advice, and an MOT pass or a clean MOT history does not guarantee that a car is roadworthy today. If you are unsure about a car, have it inspected by a qualified mechanic. You can check any vehicle's MOT history free on the official GOV.UK MOT history service.
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