Grand River Water Temperature Today
Grand River, a river swimming spot in Ontario, Canada. The water reaches comfortable swimming temperatures in high summer, and is near-freezing in midwinter.
In August Grand River averages about 23°C, peaking near 23°C in July, August, September and dropping to roughly 1°C at its coldest.
River and swimming-hole temperatures are modelled from long-term monthly averages and refined with live air temperature, wind and UV. Moving water reacts faster to the weather than a lake or the sea.
Grand River water temperature by month
| Month | Average water temperature | Swimming |
|---|---|---|
| January | 2.5°C | cold |
| February | 1.0°C | cold |
| March | 2.5°C | cold |
| April | 6.5°C | cold |
| May | 12.0°C | cool |
| June | 17.5°C | mild |
| July | 21.5°C | warm |
| August | 23.0°C | warm |
| September | 21.5°C | warm |
| October | 17.5°C | mild |
| November | 12.0°C | cool |
| December | 6.5°C | cold |
Grand River swim conditions FAQ
What is the water temperature in Grand River right now?
In August the water in Grand River averages about 23°C. We refine that long-term average with today's air temperature, because this river responds quickly to the weather.
When is the best time to swim in Grand River?
The comfortable swim season — 18°C or warmer — runs through July, August, September, with the warmest water in July, August, September at around 23°C.
Can you swim in Grand River in winter?
Yes, but winter temperatures drop to roughly 1°C. Below 12°C, cold-water shock is the main risk: enter slowly, never swim alone, and limit time in the water.
Is Grand River safe for swimming?
Moving and inland water carries different risks from the sea: check flow after rain, avoid weirs and undercut banks, look for submerged rocks before jumping, and respect local access rules and water-quality notices.
Water safety tips
- Check the flow rate after heavy rain — inland water can rise and speed up within hours.
- Never jump before checking depth and submerged rocks; levels change through the season.
- Enter slowly to control cold-water shock, and get out before you start shivering.
- Swim with someone else and agree an exit point downstream before you start.
- Winter water here can be near freezing; treat it as a cold-water swim.
Swim season here: July, August, September.
Nearby swim spots
More swim spots in Canada
- Elora Gorge water temperature
- Ottawa River water temperature
- Rideau River water temperature
- Rivière Rouge water temperature
- Rivière Jacques-Cartier water temperature
- Bow River water temperature
- Kananaskis River water temperature
- North Saskatchewan River water temperature
- All rivers & swimming holes
- All lake water temperatures
- Sea temperatures in Canada