Kihei golf courses have great weather year round. The difference in temperature between winter and summer is hardly noticeable here and the courses are in prime condition, all year long.
One thing that you should keep in mind about the Kihei golf courses is that they are affected by the wind in the afternoons. The best time to go is at the very beginning of the day. Unfortunately, this is also the most crowded time of day so reservations are required. However, if you would like to just show up and golf, and perhaps even get a lower rate you can go for an afternoon round. Due to the wind, the afternoon is normally not as busy. Many of the courses even offer afternoon discounts.
If you forgot to bring your clubs this is normally not a problem. Most of the courses on Maui offer rental clubs. If you do need clubs and you are going at a busier time of day it is advised to reserve the clubs at the same time you make your tee time.