Rob Gronkowski Retweets Good Morning America's "69 Days Until Summer" TweetBy Stephen Douglas | Apr 13, 2016None69 DAYS UNTIL SUMMER! ☀️ ? pic.twitter.com/61HmOsaC2l— Good Morning America (@GMA) April 13, 2016 69 days until summer?Nice.But does Rob Gronkowski know this?Yes, Gronk knows.