On Earth, we have problems with rain and other forms of precipitation: either it's absent for too long and it causes droughts and ecological disasters, or it's way too plentiful and it causes massive floods and human misery. it's also hard to predict when the rain would fall and rain, snow, hail and so on that falls at the wrong time has been known to cause significant safety problems and ruined moments.
So I was considering to have the society in my fictional Earth world to have geo-engineered the global weather system such that there is a predictable amount of rain, snow, hail, or other forms of precipitation every day of the year, but at the same local time of day. In effect, it's a perpetual precipitation system that is perpetually maintained at a certain position relative to the position of the sun, but as Earth rotates, the system would not move along with it, instead staying in that position above the planet. This system would have been activated roughly within the next century and already been running for a couple centuries by the time the story happens.
This example is purely hypothetical: if the system was designed to always rain at 3 AM, it would stay in a location such that the time zone where it is currently 3 AM (in this world time zones are not the mess they are on our planet Earth) would always be directly underneath it. It would always rain at 3 AM in this example no matter what part of the planet you look at, and while the rest of the day would have a variety of sun, overcast weather, wind and temperature change like a day on our Earth has, rain would only fall at 3 AM.
One consideration I have already made is that not every region would want rain at the same time of day, and some areas might want rain more than once per day or not every day. So I would also accept solutions where the rain is more or less frequent than once per day, as long as the rain cycle itself would actually be predictable in when it happens and how much falls out of the sky.
The problem I have is that I do not know nearly enough about global ecology and the rain cycle to gauge whether this idea would actually be an improvement over our current situation from that perspective. There are probably considerations that I haven't made, like the effects on animals, and whether wild plants and animal may suffer adverse effects from this. I know there currently are already areas with wet and dry seasons which may not react to this change well. Or I might be underestimating the resilience of these systems and how it might even improve them...
Would a weather system like this be problematic for Earth's ecology as a whole? Or would it actually be an improvement long-term over the current "it happens whenever it happens" weather system?
