BY THE MIDDLE of June Mumbai, India’s financial capital, should be drenched(湿透的，浸透的). The south-west monsoon, the seasonal storm which provides most of the year’s water in South Asia, will bring torrential downpours(倾盆大雨) to the city. Street food-hawkers and builders will curse. Slum-dwelling migrant workers may head home to villages to wait for the rains to pass. Some businesspeople and financiers, meanwhile, will be patting damp pockets full of rupees(拍拍装满湿漉漉卢比的（口）袋). On May 29th India’s National Commodity and Derivatives Exchange (NCDEX) allowed traders to start placing financial bets on whether each month of this year’s monsoon will be wetter or drier in Mumbai than the average of the past 30 years.(5月29日，印度国家商品及衍生品交易所（NCDEX）允许交易者开始进行金融押注，赌今年季风期孟买每个月的降雨量是比过去30年的平均水平更湿润还是更干燥。)
到六月中旬，印度金融中心孟买本应被雨水浸透。西南季风——南亚地区每年大部分降水的来源——将给这座城市带来倾盆大雨。街头小贩和建筑工人会咒骂。居住在贫民窟的流动工人可能会返回家乡的村庄等待雨季过去。与此同时，一些商人和金融家会拍拍装满卢比的潮湿口袋。5月29日，印度国家商品及衍生品交易所（NCDEX）允许交易者开始进行金融押注，赌今年季风期孟买每个月的降雨量是比过去30年的平均水平更湿润还是更干燥。
Weather derivatives(衍生品，衍生工具), which pay out based on some clearly defined meteorological measurement(气象测量数据), have been around in America since the mid-1990s. Earlier deregulation of American energy utilities led to a niche market(一个利基市场，小众市场) in temperature derivatives, which companies could use to hedge their exposure(对冲他们的风险敞口) to “cooling degree days”, when air-conditioning demand spiked, or “heating degree days”, when households and businesses fired up their radiators.
天气衍生品，即根据某种明确定义的气象测量值进行赔付的金融工具，自20世纪90年代中期以来在美国就已存在。早期美国能源公用事业的放松管制催生了一个利基市场——温度衍生品，公司可以用它来对冲“制冷度日数”（空调需求激增时）或“供暖度日数”（家庭和企业开启暖气时）的风险。
In contrast to(与……相反，对比) conventional forms of insurance, holders have no need to prove that they have suffered a loss themselves. Instead, derivative contracts trigger automatically when some pre-agreed parameters(预先约定的参数) are met. These could be a threshold temperature, wind speed or other variable recorded in a particular place—typically an official weather station. This avoids lengthy delays in getting money to where it is most needed. Last year Jamaica’s government got a $150m payout after Hurricane Melissa’s central pressure and storm path met the criteria defined in the “catastrophe bond” the Caribbean country had issued.
与传统保险形式不同，持有人无需证明自己遭受了损失。相反，当某些预先约定的参数达到时，衍生品合约会自动触发。这些参数可以是阈值温度、风速或在特定地点（通常是官方气象站）记录的其他变量。这避免了资金在到达最需要的地方时出现长时间的延误。去年，在飓风梅丽莎的中心气压和风暴路径达到这个加勒比国家发行的“灾难债券”中所定义的标准后，牙买加政府获得了1.5亿美元的赔付。