It would be nice if a tooltip defined what met.no means by the morning/afternoon/evening/night breakdown. "Morning" could mean anything from 0 to 6h or from 6h to 12h, etc. The info could get inside parentheses alongside the label, too.
Added tooltips to the forecast table cells which will show those times. http://git.xfce.org/panel-plugins/xfce4-weather-plugin/commit/?id=2f811dd18c8337992281eaa0059018663d9eccf0