The business niche is slow on the holidays and weekends. But the health niche pick-ups on weekends and at night.
When do you notice periods when traffic to your blog slows down? Lets say you run a niche blog on fishing, hunting, hiking, camping, backpacking,,,,, there are certain times of the year when traffic will slow down because people are doing other things.
Some of my slow times are the middle summer months, holidays, and the first week of November.
The first week of november is when hunting season starts, so a l0ot of people are at the deer camp instead of on the internet.
I also notice the weekend traffic is slower then monday and tuesday traffic.
I have a couple of gift ideas sites that get about 90% of their annual traffic from mid-November to mid-December. It all depends on the nature of the traffic that you target.
"Democracy is two wolves and a lamb voting on what to have for lunch. Liberty is a well-armed lamb contesting the vote." -- Benjamin Franklin
in general I would speculate that there would be more time spent online in the winter time vs the summer time and therefore more traffic. Probably due to people being outdoors / more active more during the summer and having more time to spend online during the winter.
I could be wrong though.