Thanks. I found there is a month specific url structure for each month's magazine:
http://www.wired.com/tag/magazine-23-05/page/1
I edited the recipe so that it will dynamically find the current month's URL based on the current date and will crawl through the pages until there are no more so you can get exactly the articles from the current month's issue with no overlap/missed items.
https://github.com/kovidgoyal/calibre/pull/394/files