what's the name of that material?

[Patryk_Rebisz]

...that protects lights in bad weather (made out of wire mesh with glue in between)?

 

[RyanT]

Cello screen is what you are looking for.

 

[jax_rox]

According to my local supplier:
Screen-Glass® Also known as Hog Mesh or Celloflex

But Cello Screen brings up more Google results.

 

[Airboxlights]

According to my local supplier:
Screen-Glass® Also known as Hog Mesh or Celloflex

But Cello Screen brings up more Google results.

A good alternate to cello screen is black tar paper. Doesnt melt through quickly on large heads, less expensive. As seen on union jobs in nyc.
Cello is kind of pricey and you leave it on for a while and all the plastic melts off of the screen and becomes ineffective. Its still the standard though.

 

[Grug]

Hog Mesh is the name I know it by, never sourced it myself - but I smile heartily when the droplets start falling and the gaffer grabs it from his van.