My wife and I were talking about this a month or so ago, just before everything started to green up. We walk on a local river trail 5-6 days a week, every week, 12 months a year. We enjoy watching nature change around us through each season. One thing we love about winter is being able to see things that you can't during the growing season because the foliage blocks it. (you can see farther in the woods when trees are barren) Also, wind sounds so much different now than it does in November.
Steve, I've come to enjoy more than just winter (though I HATE hot weather) as each season brings with it unique experiences outside. We find nothing dull about the landscape in winter, we think it's just as beautiful as it is in full bloom. And walking on the trail on a crisp winter day honestly is invigorating for both of us.