That is what the forecast said several weeks before I left (I went last month) and I was freaking out but everyone told me it would be fine and that the forecast was wrong. Turns out it was almost right. The weather was kinda cruddy (if you call two days of strong wind, a decent amount of rain and overcast skies for a week crappy, diving was even cancelled for a day). I just had a terrible winter here in Wisconsin and wanted desperately for amazing tropical HOT weather...so for me it was crappy. The rain never lasted long. But....when I got there they told me that the past several months the weather had been perfect and just that week was crappy, the week I happened to be there. So.....even though it was kinda true for me, don't trust it. The forecast here for Roatan pretty much ALWAYS says the same thing.
And hey, even if there is crappy weather, do like I did...just go on as many dives as possible...and you won't know the difference. Seriously, you'll have a great time even with some showers!
Keeping my fingers crossed for you!