Enter the vertical rain speed (m/s) and the horizontal rain speed (m/s) into the Rain Angle Calculator. The calculator will evaluate the Rain Angle. 

Rain Angle Formula

The following two example problems outline the steps and information needed to calculate the Rain Angle.



  • RA is the Rain Angle (degrees)
  • RSY is the vertical rain speed (m/s) 
  • RSX is the horizontal rain speed (m/s) 

To calculate the rain angle, take the inverse tangent of the vertical rain speed over the horizontal rain speed.

How to Calculate Rain Angle?

The following steps outline how to calculate the Rain Angle.

  1. First, determine the vertical rain speed (m/s). 
  2. Next, determine the horizontal rain speed (m/s). 
  3. Next, gather the formula from above = RA = ATAN ( RSY / RSX).
  4. Finally, calculate the Rain Angle.
  5. After inserting the variables and calculating the result, check your answer with the calculator above.

Example Problem : 

Use the following variables as an example problem to test your knowledge.

vertical rain speed (m/s) = 5

horizontal rain speed (m/s) = 3

RA = ATAN ( RSY / RSX) = ?