Weather is an in-game mechanic in One Piece Golden Age. Occasionally, clouds will form in certain areas of the map. These clouds slowly move around the map and can range from puffy white clouds to potentially dangerous dark clouds that may gradually form. The following weather can happen in-game as of now:
A rain effect will appear on screen alongside sounds of rain. It seems to have no effect on the gameplay and is simply for aesthetics
Thunderstorms involve frequent bursts of lightning mixed with rain within the area of the storm cloud. These flashes of lightning have the potential to hit players and cause significant damage to you. The lightning strike's damage can range from anywhere between 1,000 - 1,800 damage, so it isn't recommended for anyone under level 40 or so to be out in a thunderstorm as you will likely die from a hit by lightning. (Getting hit by lightning and surviving will earn you a badge)
Note: Logia Devil Fruit users can not be struck by lightning, thus not being able to earn the badge.