Why do pet stains reappear when it's humid?
Answer: Sounds like you have a bad stain on your hands! When spots reappear, that’s a sign that the spot or stain has gone into the padding below. Here’s what you should do; pretreat the stain with an enzyme action based product such as Pet Stain & Odor Pre-treat for Carpet & Upholstery for 48 hours. Then give your stubborn stain one more go with your upright carpet cleaner.
To make sure you reach the padding of your carpet, run your carpet cleaner back and forth over the spot until you no longer see color coming up from the clear nozzle on your carpet cleaner.
After carpet cleaning, if spots happen to come back again, just touch it up with OxyPro® and let stand overnight.