Online, it seems a lot of sources say LIDAR doesn't work as well as RADAR in rain or humid, dewy weather. Maybe it's obvious, but I was essentially just wondering why. Why does water in the air affect light waves more than radio waves?

3 hours ago, Ericchiriboga said:

Online, it seems a lot of sources say LIDAR doesn't work as well as RADAR in rain or humid, dewy weather. Maybe it's obvious, but I was essentially just wondering why. Why does water in the air affect light waves more than radio waves?

Scattering. Visible light tends to be scattered by tiny droplets in the air, whereas radio waves are not because their wavelength is far longer than the dimensions of the droplets. 

But I can't immediately see why simple humidity, i.e. without any condensed droplets, would weaken a LIDAR signal. 

 

Water vapor and liquid water have some strong absorption features of increasing strength as you move into the NIR and IR.

https://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water