Lots of unhappiness about weak September U.S. retail results. Some of that can be blamed on a fading consumer, but there is also ample reason to think it has something to do with the weather.
Check the following figure (click for a larger version) from Weather Trends for a somewhat complex graph that shows the recent weather/retail relationship, tracking comp sales data against precipitation and average temps in major metros. The upshot? September was much warmer and drier than seasonal norms, likely driving poor cold weather clothes sales.
There will be oodles more meaty stuff on making money from weather data at my Money:Tech conference in New York this coming February.