Well yes & no. My wife purchased a new leather sofa so our old white cloth went out the door, Our trash pick up is really slow. Special pick up only. Not with the weekly pick up. Well anyway we have had about 8 inches of rain and the sofa gets soaked every other day but who cares. I don't but what's interesting is all that rain and NO browning or mildew. But the sun shines to dry out the sofa. I guess I will start doing the sofas in the driveways with a garden hose & a leaf blower. But not really. ha ha. In over 35 yrs only 1 sofa was a problem and that was from way to much resolve on the sofa arms and her two male dogs that sat on the arms with their plumbing leaking on the sofa arms. If the sofa wasn't there so long I might sell it because it looks better than when it was placed out there. Thank you Mother Nature .
Leather is the way to go. 25 years old still looks great. Although 30 year old Scandinavian Sectional looks good too. Buy quality if you want it to last. I miss SteamWay.
I keep a sofa on my front porch all year long.
Sorry I got off on the subject matter. I wonder how many times you had with brown out from over wetting. To damage the cloth and damage the cleaning . The extreme being out in the street for 2 weeks with LOTS of rain but no brown out or damage to the cloth or was it another problem and not the amount of moistier ?