Cross-country ski trails are marked according to their difficulty in accordance with DIN 32913. This standard serves as the basis for the classification into degrees of difficulty and also specifies the requirements for marking and signposting in the "organised" ski area.
- Easy cross-country ski trails are marked in blue on the trail map. This means that the route is predominantly flat. The uphill and downhill sections have a maximum gradient of 10 percent. In addition, the downhill sections may not contain any curves with a change of direction.
- Medium-difficulty trails are red. They lead over predominantly undulating terrain. Ascending and descending sections may not exceed a gradient of 20 percent. Curves in downhill sections may have a change of direction.
- Demanding trails are marked in black. The routes may exceed the 20 percent ascension mark and force the cross-country skier to change direction on curves in downhill sections.