Unfortunately, anytime can be the season for mold! There are mold spores everywhere in our environment just looking for a moist organic surface on which to grow.
If you can smell a musty odor or see mold, you have a mold problem. Reliable sampling for mold can be expensive since it requires special equipment and training. Testing is not generally recommended as a first step.
Since people react to mold whether it is living or dead, the mold must be removed. During mold removal protect your health by using a mask or respirator that will filter out mold spores. Usually it will be designated as an N95, 3M#1860 or TC-21C particulate respirator. Wear eye protection, rubber gloves, and clothing that can be immediately laundered. Dampen moldy materials before removal to minimize the number of airborne mold spores.
Mold can be removed from hard surfaces by scrubbing with a non-ammonia soap or detergent. (Do not mix ammonia and bleach; the fumes are toxic.) Mold on porous surfaces like carpeting and drywall cannot be thoroughly removed, so those materials should be discarded.
After the mold is removed, disinfect the area using bleach and water solution or another disinfectant. The amount of bleach recommended per gallon of water varies considerably, ranging from a solution of 1/4 cup bleach for a clean surface to 1 1/2 cups bleach per gallon of water for surfaces that could not be thoroughly cleaned. The surface must remain wet for about 15 to 30 minutes to allow the solution to disinfect.
Finally, rinse the entire area with clean water and then rapidly dry the surfaces. Use fans, dehumidifiers, air conditioning, or natural ventilation.
The moisture problem must be fixed to prevent future mold growth. Mold cannot grow without moisture.