Late September is the smarter pick for Niagara Falls.

Yes, if you have to choose between the two, late September wins for better weather, smaller crowds, and most attractions still running.

Early May is still shoulder season, but it’s chilly and unpredictable. You might get 50°F and drizzle. The Falls are impressive regardless, but you’ll spend less time comfortably outdoors. Late September gives you warm afternoons, crisp evenings, and far less rain