The rainy season stretches from November to February and can create difficult conditions for trekkers. Daytime temperatures hover around 70°F year-round but nights are chilly, plunging from 45°F through the rainy season to a low of 35°F in July. Cuzco is 11,155 feet above sea level: Try to eat lightly, and avoid alcohol and strenuous exercise for the first few days. Coca tea is an effective local cure for altitude sickness. The language is Spanish; the currency is the sol (plural, soles). Tipping is not standard outside of upscale restaurants (where 10% is customary), but is generally appreciated. Traditionally dressed women and children posing for photos do so for a small tip of a couple of soles. Be aware of pickpockets.