From a response on Yahoo! Answers regarding the weather on September 11, 2001: “The morning of September 11, there literally wasn’t a cloud in the sky. I still remember the anchor on Channel 7 after the first plane hit remark that with how clear it was, he didn’t know how anyone could run into the World Trade Center (that was before the 2nd one hit and we knew it was something else.) The sky was blue as blue can be. It was a beautiful early summer day.”
– shoredude2, “What was the weather like on September 11 2001 in Manhattan, New York?,” Yahoo! Answers, 2008