As Jon mentioned flax fiber has a tendancy to absorb moisture, and the relative humidity can have an impact on the fiber/matrix bonding. It’s the weak point of flax fiber composites according to papers available online.
eKoa is way less sensitive than wood to humidity variations, but I remember that Joe Luttwak said it was stable in a wide range of temperature/humidity but not completely impervious to water.
I would guess that in locations with crazy high humidity it would be wiser to stick to carbon fiber?
For where I live, I still want an El Capitan
