Hi Rafael,
Some friends and I hiked White Mountain on July 4th, 2003 to watch fireworks from the summit (tiny pin-prick fireworks from way up there!). We started in the early evening and hiked much of it in the dark, but the weather was perfectly fine. Good headlamps or a full moon are necessary, and hiking in groups is certainly recommended. Needless to say you need to be prepared for very cold temperatures and bad weather, particularly in late October. I personally wouldn't do the hike in late October, but it's an absolutely perfect summer hike to do at night. Hey-- we even saw a Bighorn sheep very close to the summit-- a rare and very memorable encounter.
Best,
Dave