Marathon Surf Break

Lat Long: 48.73° N 86.55° W

Marathon Sea Temperature and Wetsuit Guide

Issued: 1 am 23 Aug 2026 (local time)

Forecast update in  hr  min

Today's Marathon sea temperature is
17.1°C
4.0° 

Marathon surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.

Today's Marathon sea temperature is 17.1 °C

(4.0° warmer than normal for this time of year)

Mean: 13.1 °C
Range: 8.6 °C to 17.8 °C
Statistics for 23 Aug (1981–2005)

    Today, many surfers would wear a summer wetsuit.

    The Marathon water temperature is reasonably warm (17 °C) and the air temperature will similar (windchill forecast 15 °C). A good quality summer wetsuit would be ideal.

    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 Surf-Forecast.com 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.

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