Australia's catastrophic east coast floods have been described by the NSW premier as a "one in 1,000-year event, a term that has created a great deal of confusion. Lengthy explanations that these terms are not the same as "occurring 1,000 years apart" or "once every 1,000 years" have only added to the confusion. The simplest explanation is that the actual meaning of "one in 1,000 years" is "having a probability of 0.1 percent in any given year" (1 in 1,000), which raises the question: why don't people simply say that? The main reason is that these terms date back to a time when most people didn't think in terms of probabilities, and even those who did were confused about how they worked. The daily weather forecast includes a percentage probability of rain, and longer-term forecasts give the probabilities of higher or lower than average rainfall according to El Nino and La Nina cycles.