The Price of Cotton

So I am an economist by education which means that I like to look at supply and demand curves, and analyze how shocks to the economy effect everyday life. So apparently the local temperature is a supply shock to the cotton growers all over the world. Without fail it would seem that with increased temperatures the price of cotton increases.
Now you might think that over a national market like we have in the US that supply shocks might me minimized because when it is warm in Utah its still darn cold in Wyoming or Montana, or North Dakota. But time after time I have seen the effects of this market shortage for cotton. the temperature rises and without fail the price goes up. I mean, for what other reason could it be that as the temperature increases so does the distance between women's hem lines and the ground, or the vertical distance from a woman's chin to her neckline? clearly there is a correlation between the temperature and cotton prices. And now as an honest to goodness graduated economist I will have to look into the matter.