Why do most online weather forecasts only state the chance of rain as a percantage, without stating the expected rainfall in millimetres? If there’s a 90% chance of rain, it matters a lot whether it will be 0.5 or 5mm

Question

Why do most online weather forecasts only state the chance of rain as a percantage, without stating the expected rainfall in millimetres? If there’s a 90% chance of rain, it matters a lot whether it will be 0.5 or 5mm

In: 29

Answer 1

The precipitation forecast is usually also available when you have the forecast in more detail.

But generally you have more chances of getting rain if you have bigger clouds, and bigger clouds means more water to rain, so it’s a good starting point, if you need more info it’s generally available too. The probability is more like a headline