Whats its like there in the rain?

Hi all,

I'm looking for insights on what to expect for a trip to the Wailuku area March 11 - 18. I just noticed significant rain in the forecast, but am hopeful for some patches of sun. Our group of three includes an adult with a mobility disability (not wheelchair but extremely limited mobility), a 5 year old, and an able bodied person. This is a once in a lifetime trip for our family and I want it to be great even if it rains.

Curious about the weather in general - never been to Hawaii so I'm unfamiliar with weather patterns. I'm also curious about recommendations for accessible and kid friendly fun.