stratus/fog
Clouds. But technically it is falling from the sky, from clouds in the sky.
Stratus
No, clouds out of a blue sky would not affect lightning or lack of it
Well the condtion doesent revolve around the sky. the sky stays the same at all times. But if there are clouds in the sky then the condtions revlove around the clouds. For excample, of the wind direction you could see which way the clouds were going.
Clouds, sky, mosquitoes 
no only the black clouds which is made by the condenstation will give rain
The sky is higher than the clouds. The sky is the space above the Earth's surface where the clouds, sun, moon, and stars are located. Clouds are formations of water droplets or ice crystals suspended in the sky.
When there are no clouds in the sky, the weather is usually clear and sunny.
The color of clouds in the sky can vary, but they are typically white or gray.
Clouds occupy the sky for separate reasons. The sky is always blue, except when the sun's elevation is very low (sunrise/sunset) or on very hazy days. It is blue due to the way the atmosphere scatters the sun's light. This has nothing at all to do with why clouds might exist in the sky on a particular day.
the troposphere is where clouds form or if you want it to be simple clouds are in the sky.
cirrus clouds