Most UK drivers run the same tyres all year and never think about it. That works for a lot of people, but not everyone, and the difference on a cold morning is bigger than most drivers expect.
The 7 degree rule
The dividing line is roughly 7°C, and it has nothing to do with snow. Summer tyre compounds are designed to work in warmth. Below about 7°C the rubber stiffens, the tread stops keying into the road surface, and grip falls away on a dry road as well as a wet one.
Winter compounds stay flexible in the cold. That is the whole point of them. The deep tread and the fine slits across the blocks, called sipes, matter too, but the compound is doing most of the work.
A cold, dry January morning is a winter tyre's argument, not a snowy one. Snow is rare in most of the UK. Sub 7°C mornings are not.
The three types
- SummerBest dry and wet grip above 7°C, shortest braking distances in warm conditions, quietest and most fuel efficient. What most UK cars run year round.
- WinterDramatically better below 7°C, on snow, ice and slush. Softer compound wears faster in warm weather and feels vaguer in summer.
- All seasonCompetent year round, never the best at either extreme. A genuine compromise rather than a magic third option.
Which should you actually buy?
Summer tyres if you drive mainly in towns and cities, mostly on gritted roads, and can leave the car when conditions are severe. That is the majority of drivers in England and Wales.
Winter tyres if you live somewhere rural, hilly or exposed, if you have to get to work whatever the weather, or if you drive regularly in Scotland or the north in winter. Also worth it if you drive in Europe, since several countries make them a legal requirement in winter months.
All season tyres if you want one set that copes with a cold snap, do not want to store and swap two sets, and do not routinely see deep snow. They are the sensible answer for a lot of UK drivers who want more cold weather margin without the faff.
The marking that actually counts
Two symbols get confused constantly:
- M+SMud and snow. Self declared by the manufacturer with no test behind it. Means very little on its own.
- 3PMSFThree peak mountain snowflake. Independently tested for severe snow performance. This is the one that counts, and the one European winter tyre laws recognise.
Any tyre you buy for genuine winter capability, whether winter or all season, should carry 3PMSF. If it only has M+S, treat it as a summer tyre with an aggressive tread pattern.
Swapping between sets
If you run two sets, the rule of thumb is to fit winters when the clocks go back and summers when they go forward. That maps closely enough to the 7°C average in most of the UK.
Fit all four. Mixing winter tyres on one axle and summers on the other gives the car two completely different levels of grip front to rear, which is worse than running summers all round.
Store the set you are not using somewhere cool, dry and out of direct sunlight. Stack them flat or hang them, and mark which corner each came from so you can rotate them properly next time.
Do winter tyres cost more to run?
You are buying two sets, but you are also only wearing one at a time, so the total mileage cost is closer to a single set than it looks. The real costs are the swap fee twice a year and somewhere to keep the spare set.
Against that, winter tyres in cold conditions cut stopping distances substantially. Whether that is worth it depends entirely on where and when you drive.