Needless to say we tried to stay under umbrellas most of the day. We were able to get little umbrellas for our drinks so that was fun!
Why is it bad luck to open an umbrella inside? I did some research and here is what I found:
The most common stems from the days when umbrellas were used mainly as protection against the sun. To open one indoors would be to insult the local sun god (especially Ra) and invite his wrath on everyone in your household.
Another theory borrows from the idea of an umbrella as a protector against the storms of life. If you were to open one in your home, the household guardian spirits might think you felt their protection was insufficient, and then they'd leave in a huff. Once again, everyone in the house is cursed.
It isn't always bad luck to open an umbrella inside. According to some, it's only considered bad if any of the following apply:
-The umbrella was a gift.
-The umbrella is black.
-The umbrella has never been used outdoors.
-There is a sick person in the house.
Other bad luck umbrella superstitions:
-Never give an umbrella as a gift.
-Never pick up an umbrella you dropped (ask someone to do it for you).
-Never place your umbrella on a table or a bed.
-If a single woman drops her umbrella, she'll never marry.
(I can personally testify that this last one is NOT TRUE)