Marathon Water Temperature and Wetsuit Guide

The water temperature (2 °C) at Marathon is close to freezing. You will need a good quality thick winter wetsuit, a neoprene hood, gloves and boots; despite the sunshine. Relatively mild air temperature compared to the water temperature and a windchill factor of (13 °C).

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

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.

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

Marathon sea water temperatures peak in the range 9 to 18°C (48 to 64°F) on around the 23rd of August and are at their minimum on about the 19th of March, in the range 1 to 2°C (34 to 36°F). The highest sea 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 minimum sea 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.