The first half of April was cooler than average at DFW. In 120 years of record keeping, April 1-15, 2018 was the 17th coolest. But what does a cooler than average start to April mean, if anything?
I took the top five coolest Aprils for the time period April 1-15. I then looked to see how the following summers turned out. What I found that that three of the five did have a cooler than average summer. In fact those three summers were in the top 25 coolest of all time.
The other two Aprils went on to produce a warmer than average summer, and a normal summer.
Given that April 2018 is the 17th coolest start to April, I don't know if it will correlate to a cooler than average summer, but I'm sure hoping it does.