• of course having one dedicated palette for each level (or group of levels), would be a solution for specific users
• for general users, getting a different palette each time they change the level of a data layer, could be a headache in practice, I think
• this was proposed more than two years ago and never implemented
• implementing specific palettes based on Normals may be tricky: Normals are different following the season, the area and even the country (each country computes Normals)
• this kind of palettes are used by experts (meteorologists, climatologists, forecasters, researchers)

Original post in this thread was not about not pertinent palettes at some atmospheric levels:

• it was about incomplete palette legends displayed on map
• best sample I found (below) in support to this proposal is a worldwide temperatures map at 150 hPa
• here, all values are in purple color ranges on default palette, while palette legend on right-bottom side of the map is truncated to blue color ranges
• for this T purple map, palette legend is useless and thus will be also useless such a map without legend (even if it remains "beautiful" from an artistic pov. :o)
• what happens for temperatures or wind speed data layer maps at upper atmospheric levels does not happen for humidity data layers for example, where palette legend is not truncated on map (it covers all values ranges in [0%..100%])

In current implementation (one palette by parameter), as default palettes cover anyway value ranges of a given parameter for all atmospheric levels, I wonder why couldn't they be fully displayed on the legend (I mean instead truncating them to surface level values). This would only require minimal changes; if legend width wolud be too big, then at least a control (e.g. OnMouseOver) could show it completely as an option.

Here, on upper atmosphere, temperature values on map are far outside the range values covered by the legend.