Tour guides work in a variety of environments and conditions. Museum tour guides, for instance, work indoors year-round, while nature tour guides work outside and are subject to the effects of climate and weather conditions. Typically, a tour guide's work week is very structured, though they may work more or less than 40 hours. Since they work within the travel industry, many tour guides lead tours on weekends. Some guides are employed in seasonal or temporary positions, working only during the summer months when tourism is at its peak.