My favorite time of year to hunt groundhogs in Va is mid summer, right after the farmers have mown their hay. The hay rolls are lying in the fields and make perfect cover for a shooter. Also they're the perfect height, for me, to make a first class rifle rest.
G'hogs like to dig their burrows along ditch banks and fence lines, but they'll locate right in the middle of a standing hay field too. When the hay gets cut they're sitting ducks. I'll scope a field from a distance to get an idea of their location, but even if I don't see many hogs while scoping, if I see lots of burrows I know I'm in business. Quite often when I walk out into a field to the nearest hayroll I'll see 2 or 3 pop up for a curiousity peek, if so I'll relocate to a roll with a better vantage point. I don't worry about them disappearing as I walk into the field. They'll pop back up in a few minutes. When one rares up for a looksee and I take a shot I always do a quick scan of the field, because usually a couple more will pop up as a result of my shot, curiousity does them in. I pick another active hole and start watching, relocating a little if necessary. I've moved around in a single pasture for a couple hours doing this, shooting maybe once every 10 min. Sometimes even getting a curiousity shot at a gawker within seconds of the previous shot.
I hunt both early mornings and the last couple hours of the afternoon, although you can get some mid day shots if you're patient and willing to sit in the mid day heat. I'm patient enough, but don't like sitting in a field in mid july at noon.
I use my .204 for g'hogs, so I often pass on the close shots and try to wait for 200 yd+ shots. 395 is my best so far with the .204. I grew up hunting them with a single shot .22 though and that was just as much fun. Needless to say, as a 12 yr old kid, the closer the better, LOL. I remember ambushing them at 50 ft by waiting near a known active hole.
I consider groundhog hunting to be one of my favorite shooting activities.