St. Lawrence Marathon

Cornwall, ON, Canada • April 25, 2026

Race Day Weather

partly-cloudy-day
39°
54° high
Breezy
Dry

Cool conditions, steady run

Runners will face a cool start at 41°F, gradually warming to 54°F. Wind will be from the SSW at 11 mph, with gusts up to 24 mph, creating a headwind effect. With moderate humidity at 56%, hydration should be prioritized, and runners may push their pace as conditions remain favorable.

Race day forecast available in 29 days
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A Boston-qualifier marathon that follows the beautiful St Lawrence River from Crysler Park Marina to St. Lawrence College in Cornwall, Ontario. As well as Half-Marathon, 10km and 5km distances that follow the scenic Great Lakes Waterfront Trail. Source

Area Map

Course Map

Course Map Unavailable

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When is the 2026 St. Lawrence Marathon?

The 2026 St. Lawrence Marathon will be held on Saturday April 25, 2026.

Is the St. Lawrence Marathon a Boston Marathon Qualifier?

Yes, the St. Lawrence Marathon is an official Boston Marathon qualifier.

Historical Weather

Based on 4 years of data
Avg Temp
52°F
L:45° H:54°
RunScore
7
Conditions
Rain Freq
75%
3 of 4 yrs
Wind12mph
Dew40°F

Temperature History

Range of temperatures during race hours for each year.

Detailed History

YearConditionsLow / HighRainScore

2025 St. Lawrence Marathon

Cloudy skies throughout the day with rain.

2025
rain
46°/50°Light
7

2024 St. Lawrence Marathon

Becoming cloudy in the afternoon with rain.

2024
clear-day
46°/71°-
8

2023 St. Lawrence Marathon

Partly cloudy throughout the day with rain.

2023
partly-cloudy-day
47°/55°Light
7

2019 St. Lawrence Marathon

Partly cloudy throughout the day with a chance of rain throughout the day.

2019
rain
39°/42°Light
5
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