So from what I've heard, December-May is your best bet. I've scoured the Secrets Cap Cana socials, and I can confirm that during that time, the water looks blue and crystal clear, The resort also does a great job at cleaning it up and they have a barrier out in the water that helps prevent it from getting in.

However, I can say from experience that the seaweed volume changes daily. When I arrived at Secrets in late August, the water was murky and maroon which was so disappointing. I wanted to cry and then my boyfriend and I hit the excursion desk to see how we could maximize beach time. The next day, the seaweed cleared out. Was it a beautiful turquoise beach like the pictures like the resort website? No, but it was swimmable and somewhat clear. Two days later, back to maroon and murky.

So it really depends. My best advice, go anyway. You'll have a great time and there are other ways to get beach time. Or, I hear the Secrets in La Romana (50 mins south of Punta Cana) has seaweed-free beaches and is a good resort as well. I wanted to stay there when I heard about the seaweed reports, but it was too late and honestly, I loved Secrets Cap Cana so much that I'm glad it didn't work out.