Marigold

From 1871 August Bank Holiday was the first Monday of August. In 1965 it was moved to the last Monday of August for an experimental period which was made permanent, in England, in 1971. Scotland retains the Bank Holiday at the beginning of the month.

I was born on August Bank Holiday during the period that it was at the start of the month so I always see the first Monday of August as my "Other" birthday even when it's not the date of my actual birthday. The next time that my actual and my "other" birthdays coincide will be 2024.

One of the reasons I know that it was a Bank Holiday is my dad talked about having to walk home from the hospital because there were no buses on Bank Holidays.