Lake Ontario water temperature

Lake Ontario, Oak Orchard, NY · Lake

The current water temperature at Lake Ontario is 21.0 °C (as of August 31, 2026, source: NOAA NDBC).

Lakes stratify in summer: bathing-warm on top, markedly colder a few metres down. Measurements are taken at the surface — right where you swim.

21.0 °C

Measured: August 31, 2026 · continuously updated

💧 Water 21.0° · ☀️ Air 21.9° · high today 23.8°

Temperature trend of recent weeks

Lake Ontario — Photo: Matthew D. Wilson (LtPowers) · CC BY-SA 2.5 · Wikimedia Commons

Measurement series & statistics

This measurement series includes 1294 data points since July 3, 2026.

Lowest recorded value: 10.2 °C on July 7, 2026 · highest value: 24.2 °C on August 12, 2026.

Nearby waters

Oak Orchard Creek at the Bridges, New York · 3.9 km away21.1 °C Johnson Creek at Kuckville, New York · 6.6 km away19.6 °C Oak Orchard Creek near Kenyonville, New York · 13.6 km away21.0 °C Sandy Creek at North Hamlin, New York · 22.1 km away20.4 °C Oak Orchard Creek near Shelby, New York · 28.5 km away19.2 °C

More measuring points: Lake Ontario

Sodus Point Nearshore Monitoring23.0 °C Oswego, NY (274)22.4 °C Cape Vincent22.3 °C Oswego22.2 °C Grimsby21.7 °C Prince Edward Pt21.7 °C

Frequently asked questions

Can you swim at Lake Ontario right now?
The current water temperature is 21.0 °C. See live swimming conditions, weather and quality in the BrrChecker app.

How warm is the water at Lake Ontario?
Currently 21.0 °C (updated continuously).

← All waters