Delphi is at the foot of Mt
Parnassos, and further up the mountain, at the 2,000 meter level, is the ski resort. They are skiing there right now, and you can view the activity during Greek daylight hours at http://www.snowreport.gr/snowcam/parnassos/kelaria .html Normally roads will be fine at lower elevations. Just check the weather reports before setting out from Athens.