What are the exact guidelines in being able to say Kiddush Levana on a cloudy night. If one is able to see the form of the moon through the clouds is that sufficient to be able to say a brachah or is it preferable to wait until another night.
In order to say kiddush levana we need that the light of the moon is bright enough to benefit from the light of the moon. The Mishna Berurah explains this would be if the moon is bright enough that we see its light on the ground, (obviously in a dark place that doesn’t have street lights) or if we can see things that are only visible at night because of the light of the moon. This would apply even if only part of the moon is visible and it is partially blocked, if it still is giving off enough light as mentioned above we can make the bracha. If not, wait for another night.
If there is a temporary break in the clouds and you don’t think there will be enough time to finish saying that whole bracha, l’chatchila one should not say the bracha then, but should wait, however if one is stuck it is permitted b’dieved.
426-1, M:B 3, Halichos Shlomo Rosh Chodesh 29 ftnt 44-45.