Hi, i just checked on BBC weather, and today the visibility for where i live, is rated as good.
Now i know this is kinda offtopic, but i want to know should i use this day as a fun testing of my flashlights, (i’m free and already kinda arranged with my friends) knowing tomorrow the rating of the visibility is very good?
Anyone know how much less light penetration there is when going from good > very good classification? sorry for silly questions! 
A bit pedantic for tests that aren’t of a scientific grade. Just go out there and have fun!
You are correct. But since i do this very rare, (i’m busy) and i’m really strict when doing such things, i just wanted to know will this good rating lower the visibility like 20% or even more? i just needed something for reference knowing 2 of the show off lights are modded, so every meter helps methinks. 20% can be alot.
From here ,
Good or very good shouldn,t make any difference to a flashlight, unless yours go over 5 nautical miles 
Cheers David
Thank you so much!