Lake OntarioLake Ontario at a Glance
About Lake Ontario
Lake Ontario is the easternmost of the North American Great Lakes, straddling the Canada-United States border between Ontario and New York State. It is the smallest by surface area among the five Great Lakes, covering roughly 19,000 square kilometers.
The lake offers urban waterfronts, harbors and beaches as well as islands and shipping lanes; recreational boating and commercial shipping are both important. Depths reach over 240 meters in places, and the lake is navigable to the St. Lawrence Seaway.
Formed by glacial action at the end of the last Ice Age, the lake has supported indigenous communities and later European settlement, military activity and trade. Cities and ports developed on its shores through the 18th to 20th centuries as part of continental transport networks.
Lake Ontario lies between the Canadian province of Ontario to the north and the U.S. state of New York to the south, with the St. Lawrence River flowing out from its eastern end toward the Atlantic.
- Outflow to St. Lawrence River: Water from Lake Ontario flows into the St. Lawrence River, forming the outflow of the Great Lakes system toward the Atlantic Ocean.
- Major shoreline cities: Toronto and Rochester are among the larger cities on its shores, with port facilities and waterfront parks.
Best Time to Visit Lake Ontario
For boating and warm-weather activities visit in summer (June-September); spring and autumn offer milder crowds and comfortable sightseeing.
Weather & Climate near Lake Ontario
Lake Ontario's climate is classified as Warm-Summer Continental - Warm-Summer Continental climate with warm summers (peaking in July) and freezing winters (coldest in January). Temperatures range from -7°C to 26°C. Moderate rainfall (866 mm/year).
| Month | Comfort | Temp | Feels | Rain | Sky | Humidity | Wind | UV | Daylight |
|---|---|---|---|---|---|---|---|---|---|
| January | - | -7° - 2° | -8° | 63 mm | - | - | 4.8 m/s | - | - |
| February | - | -6° - 3° | -7° | 50 mm | - | - | 4.4 m/s | - | - |
| March | - | -4° - 5° | -4° | 58 mm | - | - | 4.3 m/s | - | - |
| April | - | 1° - 10° | 2° | 75 mm | - | - | 4.3 m/s | - | - |
| May | - | 6° - 16° | 11° | 74 mm | - | - | 3.7 m/s | - | - |
| June | - | 12° - 22° | 17° | 77 mm | - | - | 3.3 m/s | - | - |
| July | - | 15° - 26° | 21° | 64 mm | - | - | 3.2 m/s | - | - |
| August | - | 16° - 25° | 20° | 76 mm | - | - | 3.1 m/s | - | - |
| September | - | 12° - 21° | 17° | 91 mm | - | - | 3.4 m/s | - | - |
| October | - | 7° - 15° | 11° | 76 mm | - | - | 3.8 m/s | - | - |
| November | - | 3° - 9° | 3° | 89 mm | - | - | 4.4 m/s | - | - |
| December | - | -3° - 4° | -4° | 73 mm | - | - | 4.7 m/s | - | - |
How to Get to Lake Ontario
Lake Ontario’s Ontario shore is easily reached from Toronto: take the Gardiner Expressway/Lakeshore Boulevard into downtown Toronto and follow waterfront signage to parks and harbourfront piers. Public transit via GO Transit (Lakeshore East/West) and Toronto’s Union Station puts you within about 800-1,200 metres of the central waterfront; highways (Queen Elizabeth Way/Highway 401) provide road access to other lakeside towns along the shore.
Tips for Visiting Lake Ontario
- If you're going to Toronto Islands, take one of the earliest ferries from the Jack Layton/Harbourfront terminal to beat day‑trip crowds and get calmer water for kayaking or cycling.
- Explore smaller towns around the lake (for example in Prince Edward County or along the eastern shore) outside peak summer weekends-these areas offer quieter beaches, wineries and historic harbors that many day-trippers miss.
- For scenic viewpoints away from the busy downtown waterfront, head to the Scarborough Bluffs earlier in the day on weekdays when parking and trails are less crowded.