In winter, you will undoubtedly need warm clothes, meant for the temperature of around 30 degrees Celsius below zero.
In summer, we recommend you to have the head-dress, that will protect you against the Sun, as well as a sunblock. The repellents against mosquitos and midges will be of use, too (it is especially true about the routes, that take part near the rivers, lakes and wetlands). Despite high temperature in the daytime, you may need a long-sleeved sweatshirt or even a windcheater in the evening.
For almost all the tours comfortable closed shoes, protecting against sand and stones, are essential.