If you have an umbrella, suddenly you have to face a rain storm with a strong wind,what determines the best position in which to hold an umbrella?

In a rain storm the rain does not fall vertically downwards due
to the strong wind. Instead it falls at an angle. The best position to hold a strong umbrella
would be against the direction of the wind. This would provide maximum protection against the
rain. If the umbrella is held in any other direction you would not be protected against the
rain.

Holding the umbrella in the direction of the wind would get
you wet and the force of the wind will push the umbrella out of your hand. Holding the umbrella
in a direction perpendicular to the wind will also lead to the creation of an aerodynamic force
due to the shape of the umbrella that will push the umbrella away from
you.