As of the time of this post, there is a big difference between the hr-by-hr forecasts for Manitou Springs and Pikes Peak.
There will be runners who wake up on Saturday morning, look out the window and say, it is a nice day for the race. It happened in 2008. In the past years and this summer, I have found the hr-by-hr forecasts to be quite accurate in predicting changes to the weather on an hourly basis as a function of elevation.
When you pick up your bib, you will be given a drop bag. You can drop the bag off with volunteers at the start line just prior to the race. It will be transported to the summit and available for pick up after the race. I will pack some clothes in mine so that if I am shivering from the race (mild hypothermia) I will have some warm duds to put on. I will probably even put in a towel to dry off. You can put in the bag anything you desire. If you are doing the double, a recovery drink is a good idea. Make sure the top is securely fastened as the bag will probably be stored outside in the rain. Wrapping your clothes in a sealed plastic bag may be a good idea. In the past, if it was a chilly morning before the start I would wear my clothes and place them in the bag prior to start.
In the upper right corner of the forecast it lists the time it was last updated. They usually update four times a day. On race day, I will check in morning to ensure there have been no significant changes from the night before.
Have a great race.