With the possibility of temperature being a factor, you'll probably need to make a race morning call. Set yourself a couple of different goals....one for when you're having an okay day and one for when you're having one of *those* days you wish you could bottle. It's usually always a good idea in a longer race to hold yourself back for at least a couple of miles.....give yourself time to warmup fully and really figure out how you're feeling. Try to avoid getting locked into thinking you have to run a particular pace (hard to do, I know....I'm the poster child for not following my own advice
). After the first couple of miles, see how you feel and if you find you're in that race gear we all dream of finding regularly, start doling out some of the extra energy. Listen to what you head is telling you, but be ready to put the hammer down on race day if your heart is telling you to go for it after the first couple of miles. I'm sure you'll do great!