Ryanair offer travel insurance policies as an add on to a flight booking, or they can also be purchased as stand-alone products. Ryanair travel insurance is offered in two levels, so you can choose the option that's right for you and your wallet.
Jamaica's rainy season coincides with ours here in Florida (I am in the Tampa area) for the most part. We have anywhere from 30-50% chance of rain daily until hurricane season is over. I didn't mean you have rain every day, all day from May to December in Jamaica, but I assume it is a lot like here in Florida.
Jamaica's hurricane season begins on June 1st and ends on November 1st. The island is very weather friendly, and we have only had a few direct hurricane hits in the past ninety (90) years. Jamaica has felt the effects of direct hits by hurricanes, mainly in August (Gustav in 2008, Charley in 2004) and early September (Ivan in 2004 and Gilbert in 1988).