I predict that the Republican nominee for President -- whether Donald Trump, or another candidate if he drops out of the race which I see as a possibility (but a declining one), will be within 5 points of Democratic nominee Hillary Clinton in the Real Clear Politics average of Presidential Polls by the time of the first Presidential Debate set for September 26, 2016 from Long Island, New York.
Elections in the past have unexpectedly tightened up after what appear to be blowout summer months.
I do not think that Hillary Clinton has the election wrapped up. I think that anyone who thinks the election is over is calling the race too soon. The three Presidential debates (unless Donald Trump decides to cancel his appearance which he may decide to do) will be crucial in determining the race.
Even if Trump decides not to debate, I think the race will tighten up by September 26. He is bound to become better at attacking Clinton who is still vulnerable on her email and Clinton Foundation revelations. Trump also has yet to run any direct attack ads, all negative ads have been run by affiliated PACS but not by the Trump campagin directly, and he is raising funds from direct contributors.
To quote former New York Yankee baseball great and modern philosopher, and The game ain't over 'til it's over. Yogi also said that "this feels like deja vu all over again" which is another way of looking at the 2016 race.