The best time to visit Ushuaia in the Tierra del Fuego is from late February through to April and May when the surrounding forests start to turn red and yellow. In January, the city tends to fill up with crowds of tourists. Summer is definitely best for trekking. The ski season runs from the middle of June through to October. Average temperatures during the summer vary between 12ºC and 15ºC. In the winter they can often fall below zero. During the summer it is light for 18 hours a day, while in the winter it remains light for just seven hours each day.