Effect of rain on gliders in flight

There is also an illusion caused by rain on the canopy that makes the
glider appear higher than it is - causing the pilot to flare higher
than normal. When you have rain on the windscreen, you should gently
fly it on; it is a surprise when you find that the height you expect
to touch the ground is not correct. Also, because you think you're
higher, you tend to fly a lower approach, so add a few feet for
obstacle clearance in rain.

There will also be a tendancy for the inside of the canopy to mist up
more, so open the vents.


Hey !

I have never heard of this wet canopy illusion, Dan, can you expand for me?
Why does this happen? Is it just from looking through the water like when looking into a pond?

thanks
bagger