The reason why sometimes night shots are noisy, has to do with the fact that most of us forget that the camera, detecting very little light, automatically increases the ISO as high as it needs to go so the shutter speed is not so slow to the point of making the images blurry.
Remember, the higher the ISO, the more sensitive the camera will be to light, but the more noise it will create.
The way to solve this "conundrum", is to:
1 - manually set the camera to a low ISO
2 - use a tripod to stabilize the camera
Give it a try and let us know how it goes.
Originally Posted by JenLongo
Mine always turn out very noisy.