Interpreting a 50% chance of rain

We have had multiple days recently where there is a threat of rain all day. The hourly forecast from yesterday was not unusual:

One of my first thoughts in seeing such a forecast is to say that there is a 50/50 chance of rain. Flip a coin. With this in mind, I would not necessarily stay inside but I would be prepared when going outside.

The idea of a meteorologist flipping a coin when predicting rain is tempting. This could lead to thinking that the meteorologists do not really know so they are just guessing.

However, this is not exactly how this information works. If I look at the hourly forecast and see 0% chance of rain or even anything under 20-30%, I am not going to worry about rain. The probability is low. In contrast, if I see 70% and above I might alter my behavior as the probability is high.

The 50/50 information is still very useful even if it leaves a reader unsure if there will be rain or not. It is not conclusive information but it is not no information or just a guess. With rain at 50%, bring an umbrella, have a coat, or do not stay too far away from shelter but do not just stay inside.

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