Hi, this was raised in an earlier thread but never really answered. (Linked at bottom).

For rain accumulation, the legend at the bottom of the window is 0 to 300 for most places this probably suffices but for where I am interested I want that scale to go to 1000+ especially if looking at periods 24hr+. I do customise my colours with distinct changes (eg blue, yellow, black rather asthetic ROYGBIV) so I can unambiguously visually see how much precipitation > 300 but it also requires I memorise the random colour palette, defeating the benefit of the legend. Viewing the custom palette is clicking into the settings or switching to another window with a screenshot. Either my goldfish memory gets put to the test.

I thought perhaps the legend at the bottom might only be able to show n intervals, so I deleted most of smaller units and that had no effect, the legend still maxed at 300 - though the layer was currently showing 500, 600, 1000+ etc

The ideal behaviour is that the legend dynamically adjusts based on what's displayed - so the max colour/unit on layer = max in legend at the bottom. Alternatively max configured = max in legend (if there can only be n unit displayed in legend this needs to either be constraint in the choice of intervals or an additional config option to apply.

I've discussed rain accumulation but would assume this is the case for all weather layers - I've not tested, but at a glance can't see impracticalies with the fixed legend scale for other layers at my location of interest.

Related post:
https://community.windy.com/topic/31236/adjustable-color-scale-on-the-bottom