When Berlin Roads Actually Start Freezing
Germany has no calendar date for winter tyres, only a condition on the road, and in Berlin that condition arrives about five weeks before you can feel it in the air. Drag the marker to the date you were planning to book the swap and the board counts how many of the last thirty Berlin winters had already had ground frost, a full air frost or a day that never climbed above zero by then.
Every row is one winter of daily observations from the Deutscher Wetterdienst station at Berlin-Tempelhof, station 433, covering the thirty winters from 1995/96 to 2024/25. Every column is one day between 1 September and 30 April, with 29 February removed so the winters line up. A day is coloured by the coldest thing the station recorded: ground frost when the minimum 5 cm above the ground fell below zero, air frost when the standard minimum at 2 m did, and an ice day when the maximum never reached zero. The 5 cm reading is the one closest to a road surface, which is why it moves first. Checked on 15 September 2026.
Most people in Berlin swap when the weather starts to look like winter. The record says that is late. Across these thirty winters the median first ground frost falls on 30 September and the median first air frost on 6 November, a median gap of 35 days, and in sixteen of the thirty the first ground frost came in September. Put the marker on 1 November, which is roughly when the city queues at the garages, and the ground had already frozen in twenty-eight of thirty winters. Pull it back into early October and the count drops sharply. The yellow cells are the ones worth looking at: those are nights when the road froze and the air did not, which is exactly the condition named in the road traffic rules and the one you cannot see from a window.
A condition, not a date
German law has no month in it. Paragraph 2 section 3a of the road traffic rules requires winter-capable tyres whenever the road carries black ice, packed snow, slush, ice or Reifglaette, which is frost slickness. The last of those five is the one that catches people, because it happens on an ordinary cold morning that does not look like winter from indoors. Von O bis O, October to Easter, is a motoring club memory aid and carries no legal force, although October is a sensible deadline to treat it as.
Why the ground freezes first
The Deutscher Wetterdienst records two different minimum temperatures every night: the standard air minimum at 2 m that ends up in a forecast, and the minimum 5 cm above the ground, which is the reading closest to a road surface. The service’s own definition of ground frost says that it can occur while the measured air temperature is still 3 to 5 degrees. That is the whole gap this board draws. Bridges and flyovers turn earlier still, because cold air reaches them from underneath.
What the thirty winters agree on
They disagree about almost everything else. Frost nights per winter run from 23 to 130 in this record, ice days from none at all in 2019/20 to 51 in 1995/96. What they agree on is the order: the ground turns in early October and the air turns in early November. The earliest first ground frost in the set is 17 September and the latest is 12 November, while the first air frost has never arrived before 18 October.
Only the Alpine symbol counts now
Since 1 October 2024 a tyre is only treated as a winter tyre in Germany if it carries the Alpine symbol, the mountain with a snowflake inside it, also written 3PMSF. The older M+S marking on its own stopped being enough when the transition period ended on 30 September 2024. All-season tyres are fine as long as they carry the same symbol. The legal tread minimum is 1.6 mm and the ADAC recommendation for winter tyres is 4 mm.
What the board cannot tell you
It is a climatology, not a forecast. It says what happened in thirty past winters at one station in Tempelhof, which is useful for choosing a booking date in September and useless for deciding whether to drive tomorrow morning. For that, check the current warning situation and look at the road, not at the thermometer in the car, since the car reads the air and the grip problem is on the surface.
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Winter Tyres in Berlin: When the Road Actually Freezes
German law gives you no date for winter tyres, only a condition on the road. Thirty winters of Berlin-Tempelhof records put the median first ground frost on 30 September and the median first air frost on 6 November, a gap of five weeks you cannot see from a window.