The weather is the most important thing when night shooting, it can make or break any shoot, unless you are inside, whats going on in the sky is a large element of night shooting. If there is full cloud, the night is almost pointless, there will be no sky detail and it will be orange, which will reflect on your subject matter, changing the colours you light paint with.
If there is a clear sky everything is perfect, star trails in the sky, possibly a moon, tones remain as they should be. Even when it is partly cloud this can be good for your shots creating amazing cloud movement streaking across the sky really helping to fill out the negative space.
The image on the right demonstraight a typical weather report, not typical in the form the the actual weather we very rarely get a clear sky all night long. We look at the times first, sunset is 20:14 shooting wouldn't be advisable until at least 21:14 this first hour after sunset is called blue hour. some desire blue hour but for me shooting in it is impossible. It's still too light for any light painting, no stars have come out yet I often use this time to look around my location finding decent angles and spots. Same applied with the sunrise at 6:01 it's best you finish shooting by 5:01 because the hour before sunrise is also blue hour and still bad for night shots and light painting.
The temperature is also an import part of the weather because I will know what sort of clothes and provisions to take with me. Often weather sites will say 2 temperatures, 1 will be the actual temperature the other will be what that temperature feels like. It could be 5°C but feel like -2°C again useful information for clothing.
The wind also has a large impact on this, if I can see there will be partial cloud coverage but it will be very windy, I know this will make good cloud trails in my photo. If it says full cloud but very windy from the north I can check on a map in the north to see if it is clear or cloudy, this may mean the clouds will pass later in the night.
Visibility is obviously an important factor, is can be a clear night but with bad visibility, often a transparent haze will sit between you and a perfectly clear sky ruining your night, this can be caused by a number of things and is unavoidable. Don't always rely on one weather checking service, use 3 or 4 and compare your results. I have been on one weather site that says it will be starry all night and another saying it will be cloudy all night, in these situations keep looking and hopefully the one with most votes will be the correct one. The weatherman has told me it is clear, I step out the door and see full cloud coverage, the weatherman is sometimes wrong! Meaning if the weatherman says it's cloudy there is still no harm in sticking your head out the window to check.
Never go out without checking the weather because it will rain the one time you don't check it. It is very important to check the weather a few days either way If you are draining, although the weather maybe ok on the day, if it rained for 3 days previously the overflow reservoir could give way at any time and the storm drains will be filled, if you are down there when the barrier overflows then you will drown. I have many concerns about drains because I have had a few friends die while draining, I will not do it myself because of those reasons but I would prefer to make sure people are educated before doing it themselves.