Uluṟu–Kata Tjuṯa has a mostly dry climate. Rainfall is usually low, very hard to predict. The park gets an average of of rain per year, but each year can be very different. Rain is most common between November and March. Droughts are common and can be very long. The most rain recorded in one year was in 1974. The least amount was in 1965. The year 1965 was also the end of the longest drought that has been recorded here, which lasted six and a half years. Major rainfalls (periods with lots of rain) are rare, happening about every ten years. They are very important for refilling the groundwater supply and can put a lot of life into the ecosystems. The last major rainfall was in 2009, which got of rain.