Yep, end of '13. The latter ones are a lighter shade of blue, almost periwinkle, and speckled. Here's a true story:
In the Fall of 2013 I wandered into my local Weber dealer, and asked if they had a blue in stock. I wasn't planning to buy, just perv the lineup. He said, "no, but let me check the computer." A few minutes later he returned and said, "Weber has discontinued the blue, but they [Weber] have one more blue 22" OTG left in their warehouse. Do you want me to see if we can get it?"
I threw down my card, and picked it up later that week. To this day it sits in its box, unassembled, on a shelf in my garage. I don't have plans to use it, but that could change. I may give it to one of my boys as a house warming one day (they are 6 & 4 now).