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Marathon Water Temperature and Wetsuit Guide

(Lake Superior – Canada)

Today's Marathon sea temperature is 1.0 °C.

Statistics for 16 May (1981–2005) – mean: 2.3 °C, range: 1.6 °C to 3.2 °C

The water temperature (1 °C) at Marathon is close to freezing. You will need a thick winter wetsuit, a neoprene hood, gloves and boots despite the sun. Expect relatively mild air temperatures and a windchill factor of (7 °C).

Canada Sea Water Temperature

Map of current Canada
Surface Water Temperatures
based on measurements from oceanographic satellites
Canada Water Temperature Anomaly

Map of current Canada
Sea Water Temperature Anomalies

(compared with long term averages
at this time of year)

(click thumbnails to expand)

Below is a graph of Historical Sea Surface Temperature for Marathon. This has been derived from analysis of two decades of oceanographic satellite measurements of nearby open water. We have calculated the average water temperature variation around the year as well as the extremes that have been observed on each date.

Marathon Water Temperature Graph

All of the graphs for the surf breaks presented on are on the same scale to enable comparison between locations around the world.

Marathon water temperatures peak in the range 9 to 18°C (48 to 64°F) on around the 23rd of August and are at their coldest on about the 19th of March, in the range 1 to 2°C (34 to 36°F). The highest water temperatures at Marathon in the fourth week of August are ideally suited to a 4/3mm wetsuit + 3mm boots, although a 5/3mm wetsuit may be preferable for longer sessions and cold windy days. The coldest water temperatures at Marathon mean that you will need a flexible 6/5/4mm wetsuit or a well fitting 5/4mm wetsuit with gloves and 5mm neoprene booties and a hood to surf here in the third week of March.

Actual sea surface water temperatures close to shore at Marathon can vary by several degrees compared with these open water averages. This is especially true after heavy rain, close to river mouths or after long periods of strong offshore winds. Offshore winds cause colder deep water to replace surface water that has been warmed by the sun. Air temperature, wind-chill and sunshine should also be considered before deciding on the kind of wetsuit needed to stay warm when surfing at Marathon. Refer to our detailed weather forecasts for this information.