It seems like they predict where the market's gonna go the next day. How is this possible? Does anyone know where to get S&P Futures quotes? Thanks.
Is not possible because they dont'. Fut market is opened 23:15hs a day and show you where is the market a that speficic moment, so, its not a prediction is just a picture of the sentimient at that specific time. You can get delayed data from www.cme.com or www.barcharts.com and realtime data from any fut broker. and is an stupid illusion that night movement can be used to predict the next day activity. Asian, european and american session have their own psicology, but none of them can tell you what its going on in the future.
Maybe the OP is thinking of when a talking head on TV says something like "the S&P futures indicate an up open". The perceived total value of US corporate equity is always moving around 24 hours a day as we humans get bombarded with news and events. Think of the stock market as a little window we use to peep at those values. The futures market window is ~23 hours wide and the stock market window is ~7 hours wide.