In Israel, the rainy season lasts from mid-October through March, bringing humid and cool weather. Mildew thrives during this period. Its spores can cause severe allergic reactions, creating a health issue.
The rules for mildew in clothing were like those for infections in people. If the mildew spread, it was serious. If they could stop, wash, or cut it out, they could save the garment. This process was also similar to treating rot and mold in buildings (Leviticus 14:33–53).