Map of Lac Simon with depth contours

Lac Simon

46.8933° N, 72.0228° W

Depth contours from the 2013 government survey. Not for navigation.

Download the depth map (SVG)

Lac Simon is 35.3 m deep at its deepest point, deeper than 86% of the 1,506 surveyed lakes in Quebec. It covers 1.32 km² and lies 4.2 km southwest of Allen's Mill.

Maximum depth
35.3 msurveyed 2013
deeper than 86% of the 1,506 surveyed lakes in Quebec
Area
1.32 km²
larger than 78% of the 29,407 lakes in Quebec
Shoreline
6.3 km
longer than 68% of the 29,407 lakes in Quebec
Water clarity
4 mSecchi depth, 2025
clearer than 53% of the 805 monitored lakes in Quebec
Elevation
171 m

Today on the water

YELLOW ADVISORY - FROST · issued 4:39 a.m. EDT
Temperatures will drop to near the freezing mark overnight tonight.

Take preventative measures to protect cold-sensitive plants, trees, and crops.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to QCstorm@ec.gc.ca or post reports on social media using #QCStorm.

Official alert on weather.gc.ca · expires 8:39 p.m. EDT

4.1 °C

Wind calm

Observed at Donnacona, as of 5:00 a.m. EDT

choppy Estimated waves, next 12 hours: up to 0.2 m. Around 9 a.m., wind from the west: the west shore is sheltered, waves build toward the east shore.

Hourly forecast, next 24 hours
Time6 a.m.9 a.m.12 p.m.3 p.m.6 p.m.9 p.m.12 a.m.3 a.m.
Wind km/hW 15W 20W 20W 20W 20W 20W 20W 20
Gusts km/h40404040
Waves (est.) m0.10.20.20.20.2
Temp. °C7810119521
Precip. %303030300000

Today: A mix of sun and cloud with 30 percent chance of showers. Wind becoming west 20 km/h gusting to 40 this morning. High 11. UV index 3 or moderate.

Weather: Donnacona (local forecast), as of 5:02 a.m. EDT

Sun and moon

Civil dawn
6:27 a.m.
Sunrise
6:57 a.m.
Sunset
6:12 p.m.
Civil dusk
6:42 p.m.
Moonrise
5:47 a.m.
Moonset
5:30 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

24% of Lac Simon is deeper than 20 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 2013 records a maximum depth of 35.3 m, drawn from 41 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 m.

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

Photos

Décharge du Lac Simon
Photo: Gabriel Picard, CC BY-SA 4.0, via Wikimedia Commons
Lac Simon - Vue aérienne (2)
Photo: Gabriel Picard, CC BY-SA 4.0, via Wikimedia Commons