Map of Lac Saint-Joseph with depth contours

Lac Saint-Joseph

45.9743° N, 74.3319° W

Depth contours from the 2012 government survey. Not for navigation.

Download the depth map (SVG)

Lac Saint-Joseph is 32.1 m deep at its deepest point, deeper than 84% of the 1,506 surveyed lakes in Quebec. It covers 3.4 km² and lies beside Domaine-Bastien.

Maximum depth
32.1 msurveyed 2012
deeper than 84% of the 1,506 surveyed lakes in Quebec
Area
3.4 km²
larger than 88% of the 29,407 lakes in Quebec
Shoreline
33.5 km
longer than 93% of the 29,407 lakes in Quebec
Water clarity
4.1 mSecchi depth, 2025
clearer than 55% of the 805 monitored lakes in Quebec
Elevation
366 m

Today on the water

2.2 °C

Wind calm

Observed at Sainte-Agathe, as of 7:00 a.m. EDT

choppy Estimated waves, next 12 hours: up to 0.2 m. Around 12 p.m., wind from the west: the west shore is sheltered, waves build toward the east shore.

Hourly forecast, next 24 hours
Time8 a.m.11 a.m.2 p.m.5 p.m.8 p.m.11 p.m.2 a.m.5 a.m.
Wind km/hW 10W 10W 20W 20W 10W 10NW 10NW 10
Waves (est.) m0.10.10.20.2
Temp. °C8998520-1
Precip. %404040400000

Today: A mix of sun and cloud with 40 percent chance of showers. Wind becoming west 20 km/h near noon. High 9. UV index 3 or moderate.

Weather: Sainte-Agathe (local forecast), as of 7:03 a.m. EDT

Sun and moon

Civil dawn
6:36 a.m.
Sunrise
7:06 a.m.
Sunset
6:22 p.m.
Civil dusk
6:51 p.m.
Moonrise
5:57 a.m.
Moonset
5:40 p.m.
Moon
Waning crescent, 1% lit

Data Source: Environment and Climate Change Canada. Local times.

How waves are estimated

Significant wave height from the forecast hourly wind and the open-water distance (fetch) upwind, using the SMB method (US Army Corps of Engineers Shore Protection Manual, 1984), rounded up to the next 0.1 m. It is not a measurement: gusts, leftover swell and shoals can make water rougher. Under 0.2 m: calm; 0.2–0.5 m: choppy; over 0.5 m: rough.

Depth

31% of Lac Saint-Joseph is deeper than 10 m.

How to read it: the lake’s area is sorted from the shore to the deepest point. Where the curve is flat, large areas share one depth (flats and weed beds); where it drops, depth changes quickly (drop-offs).

The government depth survey from 2012 records a maximum depth of 32.1 m, drawn from 230 depth contours.

Not for navigation. Depths are from government surveys and may be outdated.

Water

Trophic status from the latest monitoring: oligo-mesotrophic (transition).

Clarity was measured with a Secchi disk in 22 years between 2004 and 2025; the latest annual mean is 4.1 m.

Water clarity (Secchi depth, m)
Total phosphorus (µg/L)

Photos

Another view of twilight over Lac Saint-Joseph
Photo: Gogerr, CC BY-SA 4.0, via Wikimedia Commons
Mist on Lac Saint-Joseph
Photo: Gogerr, CC BY-SA 4.0, via Wikimedia Commons
Dock view of Lac Saint-Joseph, the centre and largest island of the lake is in view
Photo: Gogerr, CC BY-SA 4.0, via Wikimedia Commons