My PR in the 5k is 18:40, run not long ago on July 4, 2016, and on a hilly course, too. The 19:12 was in terrible conditions, and during a 66-mile week of 100+ heat index running. There was one run that week wherein I ran in a heat index of 121.
You sure are an elite level excuse maker. I think you keep track of all those minor weather details and wind speeds not so you can learn from prior training or mistakes, but so you have all your excuses lined up. It's similar to the concept of asking for advice, getting advice, and ignoring the advice because you have "more guts and bigger balls" than all the people that answer your questions.
You're good for being young in your running career and a master's aged runner, but I still don't see proof that you "should be a 2:55 guy." (That proof of course being a 2:55 race performance.)
And here we go again--what a surprise. It's all just excuses, right? Temperatures do not matter, courses do not matter, and in regard to winds, what the heck, it is all the same. Every race is a carbon copy of every other race. You sound like an elite-level criticism maker who knows nothing about distance running, who sits back and spews malice toward fellow runners. What a shame.
In regard to the 18:40 5k PR, why don't you think about your question and answer it with some common sense. Do flat courses run the same as hilly courses? Had I achieved better fitness after July 4? Think.