Glacial lake · Canada
Great Slave Lake
Lake in the Northwest Territories of Canada
- Area
- 26,734km²
- Max depth
- 614m
- Average depth
- 59m
- Elevation
- 148m a.s.l.
- Shoreline
- 9,814km
- Volume
- 1,580km³
Great Slave Lake is a glacial lake in Canada. It covers 26,734 km². On average it is 59 m deep, and 614 m at its deepest point. Its surface lies 148 m above sea level.
Plan your visit
Stay, sail and get there
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The water
How warm is Great Slave Lake?
The water is warmest in August, around 13 °C at the surface, and coldest in January, around 0 °C. Even at its warmest, the surface stays below 17 °C on average: this is cold water.
The lake usually freezes over for about 214 days a year, from around 28 October to 29 May.
On the shore, afternoons reach 21 °C on average in July and -24 °C in January. The driest month is February (14 mm of rain), the wettest July (66 mm).
Average surface temperature measured by the Landsat 8 satellite between 2013 and 2021 at the point furthest from the shore (195 readings). Shallow bays and beaches are often warmer.
From above
The whole lake from space
Month by month
The year at the lake, month by month
Not a forecast: these are averages over many years. Water is the 2013–2021 average; air, rain, sun and wind are the 1991–2020 average.
Water: 2013–2021 averageClimate: 1991–2020 average
| Month | Water°C | Water high°C | Air high°C | Air low°C | Rainmm | Rainy daysdays | Sunh/day | Windkm/h |
|---|---|---|---|---|---|---|---|---|
| January | Ice | — | -24 | -32 | 21 | 5 | 1.6 | 13 |
| February | Ice | — | -20 | -29 | 14 | 4 | 4.0 | 13 |
| March | Ice | — | -12 | -21 | 19 | 5 | 7.3 | 15 |
| April | Ice | — | 0 | -7 | 22 | 5 | 7.8 | 20 |
| May | Ice | — | 10 | 6 | 43 | 9 | 12.2 | 21 |
| June | 3 | 6 | 18 | 14 | 57 | 10 | 11.2 | 19 |
| July | 8 | 11 | 21 | 17 | 66 | 11 | 9.4 | 18 |
| August | 13 | 14 | 18 | 14 | 64 | 11 | 7.7 | 20 |
| September | 12 | 14 | 11 | 7 | 46 | 9 | 5.4 | 22 |
| October | 4 | 10 | 0 | -5 | 28 | 7 | 2.4 | 18 |
| November | Ice | — | -15 | -22 | 25 | 6 | 0.7 | 14 |
| December | Ice | — | -22 | -29 | 19 | 5 | 0.7 | 13 |
Water: LakeTEMP (Landsat 8, 2013–2021). Air, rain, sun and wind: NASA POWER, 1991–2020 averages. A rainy day has at least 1 mm of rain. Sunshine hours are derived from measured solar radiation.
Size & depth
How big, how deep
- On average, water stays in the lake for about 12 years before flowing out.
- Its catchment drains 995,312 km² of land.
- About 4,351 m³ of water flow out every second, on average.
- Its shoreline is 16.9 times longer than a circle of the same area: plenty of bays and inlets.
Around the shore
What's around Great Slave Lake
Counted within 1.5 km of the shoreline in OpenStreetMap, the map anyone can edit.
Towns on the shore
- Yellowknife20,340 people
Nearest airport with scheduled flights: Yellowknife International Airport (YZF), 88 km in a straight line.
Car hire at YZF airport (Yellowknife)Discover Cars · Affiliate linkOpenStreetMap is built by volunteers: when a number is low, it may just mean nobody has mapped it yet.
Recent years
How each month compared
Afternoon high on the shore. The first row is the reference, the 1991–2020 average in °C; the years below show the difference from it: warmer in orange, cooler in blue.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1991–2020 average | -24.0 | -20.4 | -11.8 | -0.4 | 10.3 | 17.9 | 20.6 | 17.6 | 10.6 | -0.5 | -15.2 | -22.0 |
| 2020 | −2.1 | ±0.0 | −1.7 | −3.0 | −3.3 | −1.1 | −1.2 | −0.2 | −1.2 | −1.5 | −0.7 | +1.1 |
| 2021 | +3.9 | −7.2 | +0.1 | −2.6 | −1.6 | +1.0 | −0.2 | −0.2 | +1.3 | +3.3 | +2.4 | −6.8 |
| 2022 | −1.3 | −5.4 | −0.2 | −1.8 | −0.8 | +2.1 | +0.4 | +2.6 | +3.4 | +2.4 | +1.0 | −5.5 |
| 2023 | +3.9 | −4.8 | −1.8 | +3.1 | +7.6 | +1.2 | +1.6 | +1.6 | +3.4 | +3.1 | +3.0 | +7.4 |
| 2024 | −3.5 | +2.0 | −0.2 | +2.5 | +2.7 | −2.2 | +1.2 | +1.1 | +2.6 | +0.2 | −0.3 | +2.2 |
| 2025 | +4.4 | −2.2 | −3.6 | −0.6 | +2.4 | −1.6 | −2.2 | +2.3 | +4.3 | +2.9 | +2.9 | −8.0 |
+1 warmer than usual −1 cooler than usual
About these numbers
| Outline, area, depth, volume | HydroLAKES v1.0 (Messager et al. 2016) · CC BY 4.0 |
|---|---|
| Water temperature and ice | LakeTEMP v1 (Korver et al. 2024), Landsat 8 2013–2021 · CC BY 4.0 |
| Air, rain, sun, wind | NASA POWER, 1991–2020 · public domain |
| Names and description | Wikidata (Q5539) · CC0 |
| Around the shore | © OpenStreetMap contributors · ODbL |
| Images | EOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons |
Every figure is an average or a count from a public dataset. Licences and methods: data sources.
