Weatherbots are a series of robotic aerial vehicles suspended along the sky length of the Centauri Princess interior.
They number around twenty in total, and their average altitude is approximately 3 miles above the cylindrical surface of the interior (i.e. they hover in the middle, where there is zero g). This is comparable to the same kind of altitude as here on Earth, up into the troposphere, where air temperatures are sufficiently cool enough to enable the water vapor evaporated up from the rivers and lakes to condense into rain clouds. The middle ground of the cylinder is thus left clear of any aircraft or aerial transportation for straight-line travel by Centauri Princess residents, so that it is forever an undisturbed breeding ground for cloud formation, lightning and thunder.
The temperature gradient for cool-off of water vapor as it rises up (something known as the lapse rate here on Earth), happens because the sun-simulating lighting system inside the ark is always pointing downward toward the ground. The middle ground of the biosphere cylnder is thus both a cool and a dark place (apart from the lightning that is.)
Clouds on Earth get heavier and heavier through accumulation of mass in the water vapor that clumps together in the sky. This eventually leads them to dissipate and fall back to the ground as rainfall under the pull of gravity. Since there is no gravity in the center of the cylinder to exert any kind of pull on the clouds, the likelihood is that clouds will not readily dissipate into rainfall and precipitation inside the Centauri Princess, as they do here on Earth. In the original thesis published by Abdul Ahad, he therefore devised weatherbots to be necessary to electrostatically stimulate the clouds into releasing their water vapor content as rainfall.
This means there will be a lot of ear-splitting thunder inside the ark, as the sound waves would reverberate and echo back from the enclosing walls of the cylinder in all directions.