Afternoons are generally more mellow at Time Attack with fewer cars and more time in the morning to prepare. But in the heat of the summer, the mornings are better for lap times. Afternoons are better in winter, as track temps are too low in the morning. I was expecting a hot day, which was why I originally booked AM. When I saw the rain forecast, I decided that a clean, dry track will win over a few extra degrees of ambient temp. But you never know...it's always a gamble.