I'd use 'on' since a weekend is two days (or more). 'At' is more specific, for just a scaled-down area or shorter time, Whilst on/in are employed for extended durations or greater Areas. "Let's consume at an Italian restaurant at 9pm" towards "Let us consume in downtown on Friday".请您尽快回复并提供帮助，我将非常感激。如有需�