Weather and diving condition in Malaysia in October or November

I’m planning to do a diving holiday in Malaysia in October or November. The plan is to go to Sabah and either Tioman or the Perenthian islands.
How would the weather and the diving condition be in those areas in either October or November?
Due to lack of time I’ve to choose between Tioman and the Perenthian. Which one of the two are the best for diving? And as islands (with that I mean everything above the water)?
Thanks

Because both October and November are within the season of the northeast monsoon that shuts down diving along the east coast of Malaysia where both the Perhentians and Tioman are located, I would advise you to go to Tioman, and to go there in October, before going to Sabah. There are a couple of ops on Tioman that stay open through October, while on the Perhentians you'll have trouble finding anybody to take you diving. You can dive Sipadan/Mabul/Kapalai in Sabah year round, but many/most of the other Sabah destinations will also close down for the season.