Some of the colours in the output chart are difficult to distinguish from each other. In jquery.flot.min.js I found this snippet specifying colours: colors:["#edc240","#afd8f8","#cb4b4b","#4da74d","#9440ed"] which is yellow, light blue, red, green, purple. I replaced it with the following, which specifies up to ten colours before repeating (there are 9 categories at most in the display, that's for age-brackets) colors:["#FF8080","#78BEF0","#DED16F","#CC66C9","#5DBAAC","#F2A279","#7182E3","#92D169","#BF607C","#7CDDF7"] based on colours used to distinguish players on different teams in online games Then I tweaked it to this: colors:["#FF8080","#78BEF0","#DED16F","#CC66C9","#5DBAAC","#F2A279","#7182E3","#92D169","#CCCCCC","#7CDDF7"] so the 9th colour would be a light grey (only the age-groups has 9 categories and the 9th is "unknown").