Niagara Falls May 2024 Weather. Temperatures range from 45 to 68 degrees and there’s an average of ~3 inches. Get the monthly weather forecast for niagara falls, ontario, canada, including daily high/low, historical averages, to help you plan ahead.

Burst of heavy snow and strong. April and may will be warmer than normal, with rainfall above normal in the east and below normal in the west.