First frost or first slippery day: what decides the tyre change?
· 2016–2025 (synthetic)
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Across 97 cities and 912 autumns, the median gap between the first frost and the first slippery day — frost on a wet road, or snow — was 0 days. In 12% of autumns the first frost came at least a week before the first slippery day.
- Median gap from first frost to first slippery day
- 0 days
- Autumns with the first frost a week or more earlier
- 12 %
- Springs with a slippery day after the warm-up
- 0 %
Why we distinguish frost from a slippery road
A frost on a dry night is uncomfortable, but the road usually keeps its grip. Summer tyres become dangerous on a slippery road: frost on a wet road (precipitation that day or the day before), or snow. Most rules of thumb use either a temperature threshold or the first frost; we measured how far apart the first frost and the first slippery day really are, city by city.
Autumn: first frost and first slippery day by city
The table shows the average date of the first frost night (minimum at or below 0 °C) and of the first slippery day in each city, and the median number of days between them. Across all 912 autumns the median gap was 0 days; in 12% of them, the first frost came at least a week before the first slippery day.
| City | First frost (avg.) | First slippery day (avg.) | Gap (median days) |
|---|---|---|---|
| Baden · AT | 6 Dec | 9 Dec | 1 |
| Bregenz · AT | 23 Nov | 26 Nov | 0 |
| Dornbirn · AT | 23 Nov | 23 Nov | 0 |
| Feldkirch · AT | 20 Nov | 20 Nov | 0 |
| Graz · AT | 14 Dec | 19 Dec | 0 |
| Innsbruck · AT | 24 Nov | 25 Nov | 0 |
| Klagenfurt · AT | 20 Nov | 21 Nov | 1 |
| Klosterneuburg · AT | 6 Dec | 11 Dec | 3 |
| Krems · AT | 29 Nov | 3 Dec | 1 |
| Leonding · AT | 8 Dec | 9 Dec | 0 |
| Linz · AT | 5 Dec | 9 Dec | 0 |
| Salzburg · AT | 18 Dec | 22 Dec | 0 |
| St. Pölten · AT | 7 Dec | 10 Dec | 0 |
| Steyr · AT | 4 Dec | 7 Dec | 0 |
| Traun · AT | 10 Dec | 10 Dec | 0 |
| Vienna · AT | 28 Nov | 30 Nov | 0 |
| Villach · AT | 22 Nov | 25 Nov | 0 |
| Wels · AT | 9 Dec | 13 Dec | 0 |
| Wiener Neustadt · AT | 16 Dec | 17 Dec | 0 |
| Wolfsberg · AT | 17 Nov | 17 Nov | 0 |
| Brno · CZ | 25 Nov | 26 Nov | 0 |
| České Budějovice · CZ | 10 Dec | 14 Dec | 0 |
| Děčín · CZ | 26 Nov | 29 Nov | 1 |
| Frýdek-Místek · CZ | 21 Nov | 22 Nov | 0 |
| Havířov · CZ | 22 Nov | 26 Nov | 0 |
| Hradec Králové · CZ | 1 Dec | 3 Dec | 0 |
| Jihlava · CZ | 4 Dec | 6 Dec | 2 |
| Karviná · CZ | 23 Nov | 28 Nov | 0 |
| Kladno · CZ | 3 Dec | 5 Dec | 0 |
| Liberec · CZ | 22 Nov | 25 Nov | 0 |
| Most · CZ | 27 Nov | 28 Nov | 0 |
| Olomouc · CZ | 28 Nov | 30 Nov | 0 |
| Opava · CZ | 26 Nov | 29 Nov | 0 |
| Ostrava · CZ | 19 Nov | 20 Nov | 1 |
| Pardubice · CZ | 29 Nov | 3 Dec | 0 |
| Plzeň · CZ | 1 Dec | 2 Dec | 0 |
| Prague · CZ | 29 Nov | 30 Nov | 0 |
| Teplice · CZ | 30 Nov | 3 Dec | 0 |
| Ústí nad Labem · CZ | 19 Nov | 23 Nov | 0 |
| Zlín · CZ | 30 Nov | 1 Dec | 0 |
| Augsburg · DE | 21 Dec | 23 Dec | 0 |
| Berlin · DE | 20 Nov | 21 Nov | 0 |
| Braunschweig · DE | 3 Dec | 3 Dec | 0 |
| Chemnitz · DE | 28 Nov | 29 Nov | 0 |
| Dresden · DE | 26 Nov | 28 Nov | 0 |
| Hamburg · DE | 23 Nov | 24 Nov | 0 |
| Hanover · DE | 2 Dec | 4 Dec | 0 |
| Kiel · DE | 17 Nov | 20 Nov | 0 |
| Leipzig · DE | 23 Nov | 25 Nov | 0 |
| Munich · DE | 10 Dec | 11 Dec | 1 |
| Nuremberg · DE | 10 Dec | 12 Dec | 0 |
| Belluno · IT | 24 Dec | 1 Jan | 4 |
| Bergamo · IT | 9 Jan | 9 Jan | 0 |
| Bolzano · IT | 23 Dec | 24 Dec | 0 |
| Brescia · IT | 14 Jan | 13 Jan | 0 |
| Modena · IT | 8 Jan | 4 Jan | 0 |
| Padua · IT | 2 Jan | 5 Jan | 0 |
| Parma · IT | 7 Jan | 4 Jan | 0 |
| Reggio Emilia · IT | 21 Jan | 20 Jan | 0 |
| Sondrio · IT | 22 Dec | 22 Dec | 0 |
| Trento · IT | 28 Dec | 26 Dec | 0 |
| Treviso · IT | 26 Dec | 27 Dec | 0 |
| Trieste · IT | 27 Dec | 26 Dec | 0 |
| Udine · IT | 20 Dec | 20 Dec | 0 |
| Venice · IT | 22 Dec | 23 Dec | 0 |
| Verona · IT | 30 Dec | 30 Dec | 0 |
| Vicenza · IT | 2 Jan | 2 Jan | 0 |
| Białystok · PL | 6 Nov | 8 Nov | 0 |
| Bielsko-Biała · PL | 27 Nov | 29 Nov | 0 |
| Bydgoszcz · PL | 9 Nov | 12 Nov | 0 |
| Bytom · PL | 23 Nov | 26 Nov | 0 |
| Częstochowa · PL | 16 Nov | 17 Nov | 1 |
| Dąbrowa Górnicza · PL | 25 Nov | 27 Nov | 0 |
| Gdańsk · PL | 7 Nov | 10 Nov | 0 |
| Gliwice · PL | 20 Nov | 21 Nov | 0 |
| Gorzów Wielkopolski · PL | 20 Nov | 20 Nov | 0 |
| Katowice · PL | 1 Dec | 5 Dec | 3 |
| Kielce · PL | 15 Nov | 15 Nov | 0 |
| Kraków · PL | 23 Nov | 24 Nov | 0 |
| Łódź · PL | 10 Nov | 11 Nov | 0 |
| Lublin · PL | 10 Nov | 13 Nov | 1 |
| Olsztyn · PL | 3 Nov | 5 Nov | 0 |
| Opole · PL | 17 Nov | 18 Nov | 0 |
| Poznań · PL | 16 Nov | 20 Nov | 1 |
| Radom · PL | 14 Nov | 16 Nov | 0 |
| Ruda Śląska · PL | 25 Nov | 25 Nov | 0 |
| Rybnik · PL | 18 Nov | 23 Nov | 2 |
| Rzeszów · PL | 20 Nov | 25 Nov | 0 |
| Sosnowiec · PL | 28 Nov | 30 Nov | 0 |
| Szczecin · PL | 16 Nov | 18 Nov | 0 |
| Toruń · PL | 9 Nov | 9 Nov | 0 |
| Tychy · PL | 26 Nov | 27 Nov | 0 |
| Warsaw · PL | 11 Nov | 14 Nov | 0 |
| Wrocław · PL | 21 Nov | 23 Nov | 0 |
| Zabrze · PL | 20 Nov | 23 Nov | 0 |
| Zielona Góra · PL | 17 Nov | 20 Nov | 2 |
| Chur · CH | 23 Nov | 27 Nov | 1 |
Spring: cold mornings after the warm-up
In spring the question is reversed: after the 5-day average has settled above 7 °C, is there still a slippery morning? In 0% of 970 springs there was at least one. The table shows the average warm-up date, the average last slippery day and in how many springs a slippery day still came after the warm-up.
| City | Warm-up above 7 °C (avg.) | Last slippery day (avg.) | Slippery after warm-up |
|---|---|---|---|
| Baden · AT | 24 Mar | 3 Mar | 0/10 |
| Bregenz · AT | 6 Apr | 12 Mar | 0/10 |
| Dornbirn · AT | 9 Apr | 14 Mar | 0/10 |
| Feldkirch · AT | 3 Apr | 13 Mar | 0/10 |
| Graz · AT | 17 Mar | 24 Feb | 0/10 |
| Innsbruck · AT | 4 Apr | 12 Mar | 0/10 |
| Klagenfurt · AT | 8 Apr | 18 Mar | 0/10 |
| Klosterneuburg · AT | 27 Mar | 5 Mar | 0/10 |
| Krems · AT | 26 Mar | 26 Feb | 0/10 |
| Leonding · AT | 20 Mar | 23 Feb | 0/10 |
| Linz · AT | 24 Mar | 28 Feb | 0/10 |
| Salzburg · AT | 20 Mar | 19 Feb | 0/10 |
| St. Pölten · AT | 21 Mar | 2 Mar | 0/10 |
| Steyr · AT | 20 Mar | 3 Mar | 0/10 |
| Traun · AT | 22 Mar | 26 Feb | 0/10 |
| Vienna · AT | 25 Mar | 3 Mar | 0/10 |
| Villach · AT | 10 Apr | 16 Mar | 0/10 |
| Wels · AT | 17 Mar | 21 Feb | 0/10 |
| Wiener Neustadt · AT | 20 Mar | 26 Feb | 0/10 |
| Wolfsberg · AT | 31 Mar | 15 Mar | 0/10 |
| Brno · CZ | 28 Mar | 7 Mar | 0/10 |
| České Budějovice · CZ | 26 Mar | 2 Mar | 0/10 |
| Děčín · CZ | 30 Mar | 5 Mar | 0/10 |
| Frýdek-Místek · CZ | 24 Mar | 11 Mar | 0/10 |
| Havířov · CZ | 26 Mar | 11 Mar | 0/10 |
| Hradec Králové · CZ | 29 Mar | 9 Mar | 0/10 |
| Jihlava · CZ | 28 Mar | 7 Mar | 0/10 |
| Karviná · CZ | 31 Mar | 14 Mar | 0/10 |
| Kladno · CZ | 26 Mar | 7 Mar | 0/10 |
| Liberec · CZ | 29 Mar | 6 Mar | 0/10 |
| Most · CZ | 28 Mar | 3 Mar | 0/10 |
| Olomouc · CZ | 28 Mar | 12 Mar | 0/10 |
| Opava · CZ | 29 Mar | 13 Mar | 0/10 |
| Ostrava · CZ | 31 Mar | 14 Mar | 0/10 |
| Pardubice · CZ | 31 Mar | 16 Mar | 0/10 |
| Plzeň · CZ | 27 Mar | 4 Mar | 0/10 |
| Prague · CZ | 26 Mar | 2 Mar | 0/10 |
| Teplice · CZ | 3 Apr | 12 Mar | 0/10 |
| Ústí nad Labem · CZ | 28 Mar | 9 Mar | 0/10 |
| Zlín · CZ | 31 Mar | 7 Mar | 0/10 |
| Augsburg · DE | 19 Mar | 26 Feb | 0/10 |
| Berlin · DE | 8 Apr | 17 Mar | 0/10 |
| Braunschweig · DE | 1 Apr | 11 Mar | 0/10 |
| Chemnitz · DE | 30 Mar | 6 Mar | 0/10 |
| Dresden · DE | 2 Apr | 13 Mar | 0/10 |
| Hamburg · DE | 31 Mar | 12 Mar | 0/10 |
| Hanover · DE | 8 Apr | 13 Mar | 0/10 |
| Kiel · DE | 8 Apr | 14 Mar | 0/10 |
| Leipzig · DE | 30 Mar | 8 Mar | 0/10 |
| Munich · DE | 20 Mar | 25 Feb | 0/10 |
| Nuremberg · DE | 25 Mar | 1 Mar | 0/10 |
| Belluno · IT | 8 Mar | 20 Feb | 0/10 |
| Bergamo · IT | 24 Feb | 9 Feb | 0/10 |
| Bolzano · IT | 13 Mar | 18 Feb | 0/10 |
| Brescia · IT | 1 Mar | 12 Feb | 0/10 |
| Modena · IT | 25 Feb | 16 Feb | 0/10 |
| Padua · IT | 6 Mar | 11 Feb | 0/10 |
| Parma · IT | 25 Feb | 13 Feb | 0/10 |
| Reggio Emilia · IT | 26 Feb | 11 Feb | 0/10 |
| Sondrio · IT | 7 Mar | 10 Feb | 0/10 |
| Trento · IT | 10 Mar | 13 Feb | 0/10 |
| Treviso · IT | 27 Feb | 14 Feb | 0/10 |
| Trieste · IT | 8 Mar | 16 Feb | 0/10 |
| Udine · IT | 4 Mar | 10 Feb | 0/10 |
| Venice · IT | 4 Mar | 14 Feb | 0/10 |
| Verona · IT | 27 Feb | 18 Feb | 0/10 |
| Vicenza · IT | 25 Feb | 6 Feb | 0/10 |
| Białystok · PL | 14 Apr | 2 Apr | 0/10 |
| Bielsko-Biała · PL | 29 Mar | 3 Mar | 0/10 |
| Bydgoszcz · PL | 10 Apr | 22 Mar | 0/10 |
| Bytom · PL | 3 Apr | 19 Mar | 0/10 |
| Częstochowa · PL | 4 Apr | 20 Mar | 0/10 |
| Dąbrowa Górnicza · PL | 30 Mar | 13 Mar | 0/10 |
| Gdańsk · PL | 15 Apr | 30 Mar | 0/10 |
| Gliwice · PL | 6 Apr | 20 Mar | 0/10 |
| Gorzów Wielkopolski · PL | 5 Apr | 19 Mar | 0/10 |
| Katowice · PL | 31 Mar | 12 Mar | 0/10 |
| Kielce · PL | 8 Apr | 20 Mar | 0/10 |
| Kraków · PL | 2 Apr | 12 Mar | 0/10 |
| Łódź · PL | 8 Apr | 20 Mar | 0/10 |
| Lublin · PL | 7 Apr | 23 Mar | 0/10 |
| Olsztyn · PL | 13 Apr | 29 Mar | 0/10 |
| Opole · PL | 3 Apr | 13 Mar | 0/10 |
| Poznań · PL | 2 Apr | 12 Mar | 0/10 |
| Radom · PL | 5 Apr | 20 Mar | 0/10 |
| Ruda Śląska · PL | 1 Apr | 14 Mar | 0/10 |
| Rybnik · PL | 28 Mar | 13 Mar | 0/10 |
| Rzeszów · PL | 6 Apr | 22 Mar | 0/10 |
| Sosnowiec · PL | 5 Apr | 21 Mar | 0/10 |
| Szczecin · PL | 12 Apr | 22 Mar | 0/10 |
| Toruń · PL | 13 Apr | 26 Mar | 0/10 |
| Tychy · PL | 3 Apr | 14 Mar | 0/10 |
| Warsaw · PL | 9 Apr | 19 Mar | 0/10 |
| Wrocław · PL | 3 Apr | 20 Mar | 0/10 |
| Zabrze · PL | 3 Apr | 11 Mar | 0/10 |
| Zielona Góra · PL | 7 Apr | 20 Mar | 0/10 |
| Chur · CH | 1 Apr | 12 Mar | 0/10 |
Method and data
Daily mean and minimum 2 m temperature and daily precipitation from the Copernicus ERA5 reanalysis, 2016–2025 (synthetic), at the grid cell of each city. A frost night has a minimum at or below 0 °C. A slippery day is a frost night with at least 0.5 mm of precipitation that day or 1 mm the day before, or a day with a mean at or below 1 °C and at least 1 mm of precipitation (snow). The warm-up is the first day from which the 5-day average stays above 7 °C on at least 5 of the next 7 days and 70% of the next 3 weeks — the same rule as in the calculator. Reanalysis data describes a grid cell of about 50 km, not a specific road; valleys and bridges can be colder.
What this means for drivers
Do not panic at the first frost on a dry night — but do not wait for the first snow either. Plan the change for when the temperature settles below 7 °C, and make sure it is done before the first frost on a wet road. TyreSwitch checks exactly this in the 10-day forecast for your location.
Contains modified Copernicus Climate Change Service information. Neither the European Commission nor ECMWF is responsible for any use of this information. You may quote these figures with a link to this page.