Colors For the Day You Were Born
I have heard that in Thailand, the day of your birth has a very specific color. To improve your luck through the year, you should wear your "birth color" on your birthday every year. The King was born on a Monday and the entire country, as a sign of respect and love, will be wearing yellow shirts on his birthday.
Here are the days and their colors for handy reference:
Sunday - Red
Monday - Yellow
Tuesday - Pink
Wednesday - Green
Thursday - Orange
Friday - Blue
Saturday - Purple