Many people do not know that the online weather they look to, temperature, humidity and dew point, may not be accurate. Some websites reply on private weather stations that scattered around. Often these are inaccurate, even highly inaccurate. Some are accurate. The most accurate online weather I have found is the local airport weather or local news website weather. Where I live I think they may be the same. So before you run make sure you look to accurate weather. This can mean the difference between a comfortable run or not.