Thirty Island Lake
44.5691° N, 76.6049° W
Shoreline and neighbouring water from open government data.
Download the map (SVG)Thirty Island Lake, Ontario. 44.5691° N, 76.6049° W
Not for navigation. Depths are from government surveys and may be outdated.
borealbound.ca/lakes/on/thirty-island-lake/, compiled October 9, 2026
- Canadian Geographical Names Database, Natural Resources Canada. Contains information licensed under the Open Government Licence – Canada.
- HydroLAKES v1.0, Messager et al. 2016 / WWF HydroSHEDS. Licensed under CC BY 4.0.
- Census boundaries and population, 2021, Statistics Canada. Adapted from Statistics Canada. This does not constitute an endorsement by Statistics Canada.
- Fisheries Management Zones, Ontario Ministry of Natural Resources. Contains information licensed under the Open Government Licence – Ontario.
- Lake Partner Program, Ontario Ministry of the Environment, Conservation and Parks. Contains information licensed under the Open Government Licence – Ontario.
- City page weather forecasts and alerts, Environment and Climate Change Canada. Contains data from Environment and Climate Change Canada (ECCC Data Servers End-use Licence).
- Air Quality Health Index observations and forecasts, Environment and Climate Change Canada. Contains data from Environment and Climate Change Canada (ECCC Data Servers End-use Licence).
Thirty Island Lake covers 2.07 km², making it larger than 81% of the 18,731 lakes in Ontario. It lies beside Glendower.
- Area
- 2.07 km²
- larger than 81% of the 18,731 lakes in Ontario
- Shoreline
- 17.6 km
- longer than 86% of the 18,731 lakes in Ontario
- Water clarity
- 5.8 mSecchi depth, 2025
- clearer than 88% of the 1,251 monitored lakes in Ontario
- Elevation
- 157 m
Today on the water
10.2 °C
Observed at Sydenham, as of 3:00 a.m. EDT
choppy Estimated waves, next 12 hours: up to 0.2 m. Around 12 p.m., wind from the northwest: the northwest shore is sheltered, waves build toward the southeast shore.
| Time | 4 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/h | W 15 | W 15 | W 15 | NW 30 | NW 30 | NW 15 | var. 5 | var. 5 |
| Gusts km/h | 50 | 50 | ||||||
| Waves (est.) m | 0.1 | 0.1 | 0.1 | 0.2 | 0.2 | |||
| Temp. °C | 5 | 6 | 10 | 13 | 15 | 12 | 7 | 2 |
| Precip. % | 20 | 40 | 40 | 40 | 20 | 20 | 0 | 0 |
Tonight: Partly cloudy. 40 percent chance of showers this evening. Wind west 30 km/h gusting to 50 becoming light this evening. Low plus 5.
Weather: Sydenham (local forecast), as of 3:02 a.m. EDT
Sun and moon
- Civil dawn
- 6:45 a.m.
- Sunrise
- 7:14 a.m.
- Sunset
- 6:32 p.m.
- Civil dusk
- 7:01 p.m.
- Moonrise
- 6:06 a.m.
- Moonset
- 5:50 p.m.
- Moon
- Waning crescent, 1% lit
Air Quality Health Index
2 low risk
Kingston, as of 3:00 a.m. EDT
Follow this lake by email: a weekly summary of conditions.
Water
Clarity was measured with a Secchi disk in 14 years between 2005 and 2025; the latest annual mean is 5.8 m.
Follow this lake
Every Friday by email: the Environment Canada forecast and any weather alerts in effect.