Area that's completely without sun

[Azélor]

How cold do you want it to be, can you give an example of a real place ? Newfoundland is chilly compared to europeen standards.
Do you need a lot of precipitation ?

[Jasonomicon]

I'm not qualified or knowledgeable enough about climate to give a answer about clouds, etc, but what about making the area highly volcanic and instead of clouds the area has a large amount of ash/smoke cover. Just an idea although that might not fit with the environment you are trying to create.