I would say at least for when deer season is open. Most of the season is archery, but during this time there are various other seasons open that are firearms seasons. That's when you are the most likely to encounter hunters. It usually starts on the 1st Saturday of October, but sometimes it is the last Saturday of September depending how the calendar falls. It runs through the middle of January, usually ending on MLK Jr day. Some areas like Berks, Chester, and down to Philly, as well as Allegheny county, go from mid September to the end of January. The other time would be from mid April through May. That is spring turkey season. Turkey hunting is done mostly by calling, so if you hear a turkey, there is a decent chance that it is a hunter, or there is a hunter nearby. Staying away from that area is a good idea if you can.

In my opinion it is never a bad thing to be seen, regardless of if hunting is going on. And most of the time, other than when required, what you wear doesn't have to be orange. Bright and non-natural colors are great. You really want to avoid brown, black, and other dark or earthy shades. And if you can avoid it, don't walk right into an area that you know people are hunting. As seen in the article, it can end badly.