For Jenkins 2.289.1 or later.
This theme will replace the default blue weather icons with coloured icons. It requires the Simple Theme Plugin.
To add the theme go to the "Manage Jenkins -> Configure System" page and under the "Theme elements" section add the following:
CSS URL:
https://cdn.jsdelivr.net/gh/APEdevelopment/jenkins-colour-weather-icons@latest/src/jenkins-colour-weather-icons.css
NOTE the @latest in the above url will get the latest, if you want a specific version you will need to change it, for instance @1.0.0 will get the first official release.