Brandon,

I enjoyed your study. A while ago, and for similar reasons, I did a smaller study using only The Weather Channel’s 10-day temperature forecast. I might suggest conducting one additional analysis with your data: Use regression analysis to see whether the forecast temperatures correlate with the actual temperatures after controlling for the average high/low for the day.

The reason for this is that the average high and low are the best estimates of any given day’s temperatures in the absence of any additional useful information. I found that, ten days in advance, the Weather channel’s data did not add any useful info (i.e. you’d be better off just assuming the average high/low for the day). But from nine days in advance on, the forecast, while not always accurate, did provide some useful guidance. I’d be interested to see how the different services stack up in this regard.

Thanks for the interesting analysis. -Nick