A double-rope lifting system can be used both indoors and outdoors, but its use in windy conditions requires careful consideration. Indoors, it is generally safe and effective. Outdoors, windy conditions can pose challenges. High winds may cause the load to sway, potentially leading to accidents. Therefore, it's crucial to adhere to safety guidelines, which often recommend not using such systems in winds exceeding certain speeds, typically around 20-30 mph. Always check the manufacturer's specifications and local regulations for safe operating conditions.