Whanganui River Water Temperature Today
Whanganui River, a river swimming spot in Manawatu-Whanganui, New Zealand. The water peaks in the high teens to low twenties in July and August, and is mild even in winter.
In August Whanganui River averages about 10°C, peaking near 19°C in January, February, March and dropping to roughly 10°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.
Whanganui River water temperature by month
| Month | Average water temperature | Swimming |
|---|---|---|
| January | 18.4°C | mild |
| February | 19.0°C | mild |
| March | 18.4°C | mild |
| April | 16.8°C | mild |
| May | 14.5°C | cool |
| June | 12.3°C | cool |
| July | 10.6°C | cool |
| August | 10.0°C | cool |
| September | 10.6°C | cool |
| October | 12.2°C | cool |
| November | 14.5°C | cool |
| December | 16.8°C | mild |
Whanganui River swim conditions FAQ
What is the water temperature in Whanganui River right now?
In August the water in Whanganui River averages about 10°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 Whanganui River?
The comfortable swim season — 18°C or warmer — runs through January, February, March, with the warmest water in January, February, March at around 19°C.
Can you swim in Whanganui River in winter?
Yes, but winter temperatures drop to roughly 10°C. Below 12°C, cold-water shock is the main risk: enter slowly, never swim alone, and limit time in the water.
Is Whanganui 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.
Swim season here: January, February, March.