Lake Ontario water temperature in September

Is Lake Ontario too cold to swim in fall? In September water temperature in some cities of Lake Ontario is above 68°F and it is enough for comfortable bathing. Based on average water temperature observations over the past ten years, the warmest water temperature in Lake Ontario in September was 70.5°F (in Niagara Falls), and the coldest 66.9°F (in Mississauga). To find out the sea temperature today and in the coming days, go to Current sea temperature in Lake Ontario

Lake Ontario surface temperature in September

Lake Ontario cities and resorts with the values of the average water temperature in September in recent years.
For more detailed information about water temperature, surf forecast, weather and time of sunrise and sunset in any specific area of your interest, just click on a city name. For ease of search, all places are also grouped by the first letter of the name.

To find out what the water temperature was in Lake Ontario any day over a period of the last ten years, select the month

Places with the warmest average water temperature in Lake Ontario in September. Also indicated are the maximum and minimum temperatures in September for these locations based on observations over the past 10 years

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Our report for Great Lakes is compiled using satellite data together with in-situ observations to get the most reliable daily data of sea surface temperatures, surf forecasts, current temperatures and weather forecasts.