Lake · United States · Canada
Lake Ontario
One of the Great Lakes in North America
- Area
- 19,347km²
- Max depth
- 244m
- Average depth
- 85m
- Elevation
- 73m a.s.l.
- Shoreline
- 2,610km
- Volume
- 1,640km³
Lake Ontario is a lake in United States. It covers 19,347 km². On average it is 85 m deep, and 244 m at its deepest point. Its surface lies 73 m above sea level.
Plan your visit
Stay, sail and get there
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The water
How warm is Lake Ontario?
The water is warmest in August, around 22 °C at the surface, and coldest in February, around 0 °C. The surface averages 20 °C or more in August: comfortable for most swimmers.
On the shore, afternoons reach 24 °C on average in August and 0 °C in February. The driest month is February (58 mm of rain), the wettest October (91 mm).
Average surface temperature measured by the Landsat 8 satellite between 2013 and 2021 at the point furthest from the shore (128 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 | 2 | 3 | 0 | -4 | 65 | 16 | 1.9 | 27 |
| February | 0 | 1 | 0 | -4 | 58 | 12 | 2.9 | 26 |
| March | 0 | 1 | 3 | -2 | 62 | 13 | 4.8 | 22 |
| April | 2 | 3 | 7 | 3 | 79 | 14 | 5.9 | 20 |
| May | 6 | 9 | 12 | 8 | 79 | 13 | 7.2 | 15 |
| June | 12 | 16 | 18 | 14 | 83 | 15 | 7.8 | 14 |
| July | 19 | 21 | 23 | 20 | 84 | 15 | 8.2 | 15 |
| August | 22 | 22 | 24 | 20 | 74 | 14 | 7.5 | 16 |
| September | 19 | 21 | 20 | 17 | 78 | 13 | 6.5 | 17 |
| October | 14 | 17 | 14 | 10 | 91 | 15 | 3.8 | 22 |
| November | 9 | 12 | 8 | 5 | 71 | 14 | 2.6 | 24 |
| December | 5 | 7 | 3 | 0 | 82 | 15 | 1.3 | 27 |
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 6.7 years before flowing out.
- Its catchment drains 766,137 km² of land.
- About 7,746 m³ of water flow out every second, on average.
- Its shoreline is 5.3 times longer than a circle of the same area: plenty of bays and inlets.
Around the shore
What's around Lake Ontario
Counted within 1.5 km of the shoreline in OpenStreetMap, the map anyone can edit.
Towns on the shore
- Hamilton569,353 people
- Oakville213,759 people
- Whitby138,501 people
- Kingston132,485 people
- Ajax119,677 people
- Waterfront Communities-The Island65,913 people
- Belleville50,716 people
- Quinte West43,577 people
Nearest airport with scheduled flights: Frederick Douglass Greater Rochester International Airport (ROC), 53 km in a straight line.
Car hire at ROC airport (Rochester)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 | 0.4 | 0.2 | 3.0 | 7.4 | 12.2 | 18.3 | 23.2 | 23.6 | 20.5 | 14.0 | 8.3 | 3.4 |
| 2020 | +2.4 | +0.9 | +2.3 | −0.7 | −0.2 | +1.9 | +2.5 | +1.2 | +0.1 | +0.2 | +2.1 | +0.8 |
| 2021 | +0.9 | −0.6 | +2.5 | +0.7 | +0.5 | +2.4 | −0.6 | +1.8 | +1.5 | +3.0 | +0.5 | +2.3 |
| 2022 | −1.0 | +0.9 | +0.9 | −0.2 | +1.6 | +1.1 | +0.5 | +1.5 | −0.1 | +0.7 | +1.2 | +0.2 |
| 2023 | +2.3 | +2.5 | +0.5 | +1.3 | +0.7 | +0.7 | +0.9 | −0.6 | +0.6 | +1.9 | +0.3 | +2.5 |
| 2024 | +1.4 | +3.2 | +2.7 | +1.5 | +3.3 | +2.4 | +1.3 | +0.4 | +1.3 | +2.1 | +2.0 | +0.4 |
| 2025 | −0.4 | −0.7 | +1.8 | +0.1 | −1.1 | +0.6 | +1.4 | +0.4 | +0.5 | +1.8 | −0.5 | −1.0 |
+1 warmer than usual −1 cooler than usual
Nearby
More lakes nearby
Canada95.4 km² · 84 km away24°maxCanandaigua LakeUnited States42.0 km² · 89 km away24°maxSeneca LakeUnited States174 km² · 108 km away24°maxCayuga LakeUnited States171 km² · 113 km away24°maxOwasco LakeUnited States26.6 km² · 112 km away23°maxOneida LakeUnited States207 km² · 139 km away24°maxAbout 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 (Q1062) · 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.
