Half Marathon Pacing?

According to the McMillan calculator http://www.mcmillanrunning.com/Running%20University/Article%201/mcmillanrunningcalculator.htm (which has been scary accurate for me and many people I know) your half marathon pace should be 7:47, 1:41:51. 

With 15 weeks to train your fitness can improve greatly and you may end up beating that time.  You have to include a lot of other factors though, like will the race be the same level of difficulty; weather conditions -- 15 weeks from now is August, right?  Really hot conditions and humidity kill my pace!  Also, you have to factor in how long you've been running.  If you just started running, the curve for improvement is tremendous because you may drop weight quickly and improve physically quicker than if you've run for several years and have begun to plateau -- like me   My first half marathon was a 1:48 -- six months later I ran another half marathon in 1:38. 

Follow your plan,  and perhaps in another 10 or 11 weeks find another 5k to race.  If you've improved greatly on your time, use that new time and plug it into the McMillan calculator and use that pace as a guide. 

The race is in Mid Sept., so my official training start for this will be June 1st, working on finishing up my current training place which takes me through to the Chase Corp Challenge on May 28th.

I used a different time predictor, but they're all in the same neighborhood.

I hope to lose some more weight between now and then and I understand about the weather, last year the race was killer, high temp and high humidity, though I didn't race it.  Basically I'll do my training plan, but like to have an idea of where I should be for pace on my various runs, that way I can see if I'm on track to meet my race goal.  When I train I go by feel but monitor HR and pace as secondary data points.

Chris.