Plot precipitation amount (mm) as bars to distinguish from probability (%).

[Leftium]

Since both precipitation amount (mm) and probability (%) are plotted as lines:

• It makes it difficult to (quickly) tell which line is which
• The probability is an instantaneous measurement, while the amount is accumulated over the entire hour.
• When the lines cross it seems there might be a special meaning (but there isn't)

If the plot types for precipitation amount (mm) and probability (%) are different:

• The chart becomes easier to read and less confusing.
• Precipitation amount is not a continuous measurement, so a bar chart naturally represents how much rain will fall within that hour, where the width of the bar denotes the hour on the x-axis.

It is possible to combine other the other metrics into the chart, too:

References

• The case against dual axis charts
• https://weather-sense.leftium.com/

[vsergeev]

Agree this makes more sense. I'll look into switching these into bars for the next release.