Experience also indicates that in case of smoke or haze, visibility is better down sun than up sun, since the smoke and haze cause intense glare. At night, objects can be seen more easily against the moon. Experienced pilots never take off without consulting the latest weather information, even for short flights. Within cloud there is a very wide range of visibility. In thin clouds, visibility may be as high as 1 km, while in heavy rain clouds it may be only a few metres.
Stratus clouds are a particular case.
Once inside these low clouds, pilots will often find that visibility falls to zero. Taking off and landing present serious risks if these clouds extend right to the ground. Although rain on the windshield can be a serious irritation for the pilot, it does not seriously limit visibility. Even very heavy rain does not usually limit visibility to under 2 km. If the rain is associated with fog, however, it is a different matter.