Temperature: 67 Degrees Fahrenheit
Weather: Clear Sky
Season: Right before Fall
Wind Speed and Direction: 8 mph NE
That would be my favorite running conditions
Running in the rain was really fun! However, my favorite is going to have to be cool weather runs. Not over 75 or so degrees, not under 45. Foggy days are a close second though (or both of them combined!). Spring/summer are really horrible to run in when my allergies act up.
I love it when it's cold, damp and muddy. Rain make it better to. Mild days and pouring are nice. Fog add an edge to my running because I know the course. Heated dayes are ok.