Depending on the respective region or activity of the tour you can easily fall back on your own experiences or stick to the following tips. You can either state the whole year as a period time or individual months. The following tips for hiking and walking refer to regions that are located in the northern hemisphere:
- If the highest point of the tour is over 1000 m (3280 ft), it is not passable from November to (at least) April.
- If the highest point is between 1000 m (3280 ft) and 500 m (1640 ft), it can be recommended from April until November.
- If the highest point is below 500 m (1640 ft), it is passable during the whole year.
- You should recommend bike tours, even if they are below 500 m (1640 ft), only from April until November.
All those pieces of information, such as altitude or seasons, are guidelines.