Temperature Crystals

The Temperature Crystals is a legendary device rarely found when opening a cursed sea treasure cache. In order to power the device, the player must use a Thunder Crystal.

This device is used to change the temperature, thus affecting the weather. If it's cold, there is more chance for rains and thunderstorms to happens. On the contrary, if it's hot, there is more chance for sunny days with little to no clouds.

The player can check the temperature with a thermometer.

Source

 * Cursed Sea Treasure Cache