OK, I went back and looked.<quoted text>
Here's your link: http://fox8.com/weather/forecast/
It doesn't support your claim that: "18 years have been below normal summer temperatures." It doesn't say anything like that.
"Summer ends as Cleveland's hottest in 10 years
Published: Friday, September 21, 2012"
And the year before that...
"Summer hits Northeast Ohio with some of its warmest and wettest weather in years
Published: Thursday, September 01, 2011
This summer will go down as one of the warmest and wettest in the last half-century."