Especially in countries where the climate varies seasonally from being very dry to very humid. Bodhran skins tend to be quite responsive to the level of humidity in the air - becoming tight in dry conditions, and loose in damp conditions.
High humidity can leave a skin damp and loose, sounding like a wet paper bag.
Alternatively, very dry weather can leave the drum sounding high and tinny, like hitting a kitchen pot or a high tom-tom. Some bodhrans are so sensitive that even a rainy day can render them temporarily unplayable. In recent decades, some bodhran makers have added mechanisms which allow the player to mechanically adjust the tension of the skin. Bodhrans of this type are generally called 'tuneable bodhrans'. Some tuneable bodhrans employ a movable inner ring, which can be pressed against or drawn away from the skin, thereby changing the tension and pitch of the drum.