Compare the high and low temperatures in the output and you'll find some lows are higher than the highs...so the script isn't sophisticated to use one output to determine another. The same applies for the precipitation results. BUT it is useful if you take the high temperatures alone and tweak the precipitation to reflect more traditional weather patterns (five days of rain in the Bright Desert? I don't think so...).
Hey, awesome resource. I will be using this for my campaign. I gave it a 9 just because I noticed one kink, which is that some times the lows on the forecast were greater then the highs.
