Rain Angle Calculator

Calculate the angle at which rain hits a surface based on wind direction and surface orientation

Input Parameters

Calculation Results

Calculation Formula

Rain Angle (β) = Wind Direction (α) - Surface Orientation (θ)

Where:
β = Rain Angle (degrees from surface normal)
α = Wind Direction (degrees from North)
θ = Surface Orientation (degrees from North)

Results

Rain Angle: --
Absolute Angle: --
Is Rain Directly Horizontal: --

Rain Angle Calculator Calculator Usage Guide

Learn how to use the Rain Angle Calculator and understand its applications

How to Use This Calculator

  1. Enter the Wind Direction in degrees from North (0° is North, 90° is East, 180° is South, 270° is West)
  2. Enter the Surface Orientation in degrees from North (similar to wind direction)
  3. Enter the Wind Speed in either mph or km/h (this affects how the rain appears to fall but doesn't change the angle)
  4. Click the Calculate button to see the results

Understanding the Results

The calculator provides three key results:

  • Rain Angle: The angle at which rain hits the surface relative to the surface normal (0° means perpendicular to the surface)
  • Absolute Angle: The angle at which rain hits the surface relative to the horizontal plane (0° means directly horizontal)
  • Is Rain Directly Horizontal: Indicates whether the rain appears to be falling parallel to the ground

Applications

This calculator is useful in various scenarios:

  • Designing outdoor structures like umbrellas, roofs, and awnings to optimally block rain
  • Understanding how wind affects rain visibility and impact on surfaces
  • Weather analysis for outdoor activities planning
  • Scientific studies of precipitation patterns

Example

If wind is blowing from East (90°) and your roof is oriented due North (0°), the rain will hit the roof at a 90° angle from the roof's normal (directly perpendicular). The absolute angle would be 0° (horizontal).