conditional format if date in field is within the next 6 months

I wish to have a field in a column change its background colour to red only if the date in the field due in the next 6 months.

the format the date is in is: dd/mm/yyyy

Can anyone advise how I should use to do this.

I have looked at some of the conditional date occuring formats and just can not see one that allows anything more than a month.