I have used the skull cap (white) over the past few months in cool (32 - 45 F) through hot (102 today, 7617). This may sound counterintuitive, I can say it works well over all the temps I have listed. It keeps you warm when it is cold and keeps cool you when it is hot. So, I generally wear the skull cap all day long. Good value, especially as I was able to apply BTD points to my purchase.
PS, I bought the non-tie tail because I did not want to look like a pirate or give off a gangsta vibe - but that is a personal preference. I have wondered if the tie tail might keep one cooler.