It depends on what you mean by chocolate, and how long you intend to keep it.
If you want to store chocolate for year, you may want more precautions than for a week or two.
Medium Term Storage
To store for time periods on the order of several weeks:
Bulk chocolate for cooking or baking
This applies to any chocolate that will be cooked as part of a recipe, or melted down, whether it is sweetened or unsweetened.
The only major thing that can go wrong when storing bulk chocolate is bloom, the migration of cocoa butter or sugar to the surface. This causes a dusty white appearance, and some change in texture.
The chocolate itself is perfectly fine for baking or cooking applications where it is melted, and will be fully restored to quality if melted down and re-tempered.
I would store it in the coolest part of a dark pantry (lower shelf), and not worry about it too much.
Candy is something enrobed in chocolate with other major ingredients, such as a the cannonical Snicker's bar that is well known in the US, or a Godiva Assortment, or truffles.
These are much more sensitive.
During hot or changeable weather, I recommend storing them in the refrigerator. However, they will not taste at their best at refrigerator temperatures. Bring them to room temperature before eating.
Make sure that they are sealed in an air tight package (as from the manufacturer, or a zip-type bag) to prevent migration of odors, and to prevent condensation on the surface of the candy.
Long Term Storage
Good dark chocolate should last at least up to a year, if stored properly. It likes cool, dry storage conditions.
This may not apply in your climate as you have indicated.
While some sites recommend against it, if you wrap it very tightly (perhaps in foil, then plastic wrap, and in a zip-type bag), it can be frozen, and should last a very, very long time. The wrapping is to prevent condensation and odor transfer.
When thawing it, leave it in its wrappings until it comes to room temperature, and wipe off all condensation before opening. You may get some bloom, but as previously mentioned, this is not harmful. It may not even matter in many applications, and can be reversed by melting and re-tempering.