IMO, it matters when they spray if their argument is to combat global warming.
And, if they don't spray (at least here in Michigan) in the morning, noon and early afternoon then, it can't possibly be to block the suns rays getting to the surface to slowly help cool the planet.
IMO, it is common sense that; spraying in the morning and noon hours would be important times of the day to block the sunlight reaching the surface.
But, since they don't, it proves the spraying is NOT to combat global warming.
The intent therefore would have to be for flat-out poisoning of the human race (agenda 21) since every chemical in the spray (from information that has been gathered) is poisonous.