I'm going to go out on a limb and guess as there is absolutely no actual description of the data involved that your variable Breeding_month is character, meaning it contains letters. So the natural order of character months starts with April, August, .... The easiest approach would be to create a new variable that is the month number of the calendar year and use that. If you want to see text like April appear then create a custom format that will display the numeric value 1='January' 2='February' etc.   OR go back early in your data and make sure that your month variable is a date value and use a format like MONNAME to display the dates as words.   @Ameurgen wrote: Hi evry one, i need little help , i ma conducting GLM using ineraction between month and breed (see plot example below), so but GLM keep give me the months  in disorder , so please in any one have a  solution, that will be very helpful regards         ... View more