Meteorologists can't predict weather perfectly because it's very tricky to do so. It's hard to find a reliable forecast of a general condition and trend of a weather. And sometimes, when meteorologists puts the weather on the weather channel, you can see that sometimes they change, which means that they themselves can't predict "<u><em>perfect</em></u>" weather.
Answer: Because if you are uncertain of what's happening then you don't know how to deal with the situation. So in order to compensate for that not knowing, you take a risk.
