Most weather types will last a random amount of time up to 12 hours (12 minutes of real time); the exceptions are fair weather and light fog, which have a higher probability and thus can persist for longer periods. Weather duration appears to be tied to the game time, so that advancing the clock forward by several hours can shorten the duration of the current weather. Changing the game's clock by a small amount, or even setting it to the same time, also has a small chance of triggering a weather change. Some enemies are weather-dependent, appearing only during particular types of weather.