Do you put up a Birthday chart every year?
This year I decided to do it a little different. Our first unit of the year in science "Daily and Seasonal Changes", and part of that has us learning the names of the seasons, months, and ideally which months are in each season (fingers crossed).
So I made four charts, one for each season, and on each month displayed their birthdays as well! This way they may at least learn the Season their own birthday is in.