Okinawa trip in November?

Hi all,
I live in Tokyo and I am planning for a trip to Okinawa with my wife in November beginning.
We want to explored Okinawa for a week and do activities such as City tour, sightseeing and water sports including snorkel. However a bit concerned whether the weekend will be suitable for these activities especially water activities. I know Okinawa is tropical island and temperature is different from Tokyo.
Can anyone please suggest whether we should plan the trip in November beginning or maybe wait for summers ?

Thanks in advance!