How sturdy is this plastic? How will it stand up in the hot sun and cold winters? It goes together without any hardware?

Jeff
The steps are quite sturdy and the manufacturer claims they can support 400 pounds. There would be minimal flex in the plastic steps and they can handle weather well. Spas And Stuff has sold these steps for many years and our customers seem to be pleased with them. From the Specifications "Tab" under the main photo, here are the additional details from the manufacture. - Dual handrails - Drink holders and towel bars - Strong, sturdy construction - Supports up to 400 pounds - Depth (front to back) - 50 Inches - Height to Top Step - 32 Inches - Height to Handrail - Approximately 54" - Allows for easy entry into Swim Spas - Choose from redwood, taupe, portobello, espresso or grey - 32? high to top step - Snaps together with no hardware required