Panels that limit the sign to snow, rain, or fog

Panels **S-890a**, **S-890b** and **S-890c** are *supplementary panels* that are placed **under a vertical sign** (for example, a speed limit, no overtaking, etc.) to indicate that **that sign is only valid under certain weather conditions**:

- **S-890a (snow)**: the sign **only applies when there are snow conditions**.
- **S-890b (rain)**: the sign **only applies when there are rain conditions**.
- **S-890c (fog)**: the sign **only applies when there are fog conditions**.

In summary, these panels are **always found underneath another vertical sign**, indicating that **the rule of that sign only applies when there is snow, rain, or fog**, according to the symbol shown.