Map of Lac Sinclair with depth contours

Lac Sinclair

45.7886° N, 76.1579° W

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

Download the depth map (SVG)

Lac Sinclair is 39.1 m deep at its deepest point, deeper than 88% of the 1,506 surveyed lakes in Quebec. It covers 2.86 km² and lies 3.1 km north of East Aldfield.

Maximum depth
39.1 msurveyed 2012
deeper than 88% of the 1,506 surveyed lakes in Quebec
Area
2.86 km²
larger than 87% of the 29,407 lakes in Quebec
Shoreline
20.3 km
longer than 88% of the 29,407 lakes in Quebec
Water clarity
6 mSecchi depth, 2025
clearer than 84% of the 805 monitored lakes in Quebec
Elevation
240 m

Today on the water

5.7 °C

Mostly CloudyWind W 5 km/h

Observed at Chelsea, as of 3:00 a.m. EDT

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

Hourly forecast, next 24 hours
Time4 a.m.7 a.m.10 a.m.1 p.m.4 p.m.7 p.m.10 p.m.1 a.m.
Wind km/hW 10NW 10NW 20NW 20NW 20NW 10var. 5var. 5
Waves (est.) m0.10.10.20.2
Temp. °C5581111742
Precip. %6030303030000

Tonight: Partly cloudy with 60 percent chance of showers. Wind west 20 km/h becoming light early this evening. Low plus 5.

Weather: Chelsea (local forecast), as of 3:01 a.m. EDT

Sun and moon

Civil dawn
6:43 a.m.
Sunrise
7:13 a.m.
Sunset
6:29 p.m.
Civil dusk
6:59 p.m.
Moonrise
6:04 a.m.
Moonset
5:47 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

19% of Lac Sinclair 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 2012 records a maximum depth of 39.1 m, drawn from 64 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 Depths are from government surveys and may be outdated.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 14 years between 2009 and 2025; the latest annual mean is 6 m.

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