stk-code_catmod/data/gfx/rain.xml

<?xml version="1.0"?>

<!-- For sky particles, the size of the box is ignored -->
<particles emitter="box" randomize-initial-y="true">

    <spreading angle="3"           />
    
    <velocity  x="-0.00"
               y="-0.03"
               z="-0.00"             />
    
    <material  file="rain.png" clampu="Y" clampv="Y" />
    
    <!-- Amount of particles emitted per second -->
    <rate      min="100"
               max="250"           />
    
    <!-- Minimal and maximal lifetime of a particle, in milliseconds. -->
    <lifetime  min="10000"
               max="10000"          />
    
    <!-- Size of the particles -->
    <size      min="1.00"
               max="1.50"          />
    
    <color     min="255 255 255"
               max="255 255 255"   />

</particles>