Are polypropylene outdoor rugs actually weatherproof?

Across the reviewers we read, 100% polypropylene rugs handle rain, sun, and humidity well and are the dominant material in this category. Retailer reviewers consistently note they hose off easily and resist UV fading, though several Home Depot reviewers caution that thicker flatwoven styles can take a long time to dry after a heavy soaking on uncovered decks.