No. I just sat down to make the "Got Snow" design and since it's almost spring, I did that as well and printed a few of each on the same sheet of business card paper. I figured that on the off chance that we don't GET any more snow, I'd have the "spring" theme working for me as well.
I made them specifically for the top part of the card display. It didn't make sense to me to just have the same thing there(my card) as is below - waste of real estate. Since a business card isn't typically geared towards "advertising", I figured I would use that upper space for that purpose.
It's obviously designed to place a card there so that when the cards run out below, your info is still on display. Keeping that in mind, I made sure to have my logo, phone number and important points included "up there" as well.
No, I don't think season specific business cards are a good idea. That's what all other forms of advertising are for.
Finally, to answer your question about "timing"... LOL, I have no clue!
I was in Home Depot the other day and saw that all the new mowers and lawn furniture are arriving, so I figure it's not too early to advertise for spring.