I tend to use Capitol City as it is nearly always identical to me, but MDT is usually within a few degrees. Precip can vary (for instance that storm two nights ago I had 1/4 inch and they had 3/4 inch!)
Radar shows a cell directly over my house - it's lighter out now than it has been in 3 hours, zero rain. Hell, the sun's actually slightly, slightly peaking. How's that possible?