Foveaux Strait Water Temperature – Southern New Zealand
On this page you’ll find the latest Foveaux Strait water temperature data for the waters between the South Island and Stewart Island. Influenced by cooler southern currents, sea temperatures here are generally lower than in the north and can feel pretty fresh year-round. Our up-to-date readings and seasonal averages help you understand what to expect before heading out on the water or exploring the rugged southern coastline.
Current Water Temperature
The current water temperature in the Foveaux Strait along New Zealand cost today is within the range of 15-16°C. Thus, the average water temperature is about 15°C. This is cool water that may feel brisk on entry. Swimming is usually limited to short sessions, and prolonged stays can become uncomfortable without thermal protection. Many swimmers choose a wetsuit, especially for surfing or open-water swimming.
It’s important to note that these swimming tips and recommendations apply only in settled weather. When air temperatures drop below 20°C — and sometimes even below 25°C — swimming can feel uncomfortable, even when water temperatures are relatively high.
Sea Temperature Trends
Over the past month, the sea water temperature has remained largely unchanged. Overall, the sea water temperature is within the range expected based on historical data for this month.
Water Temperature and Swimming Conditions by Month
| Month | Min | Avg | Max |
|---|---|---|---|
| January | 12°C | 15.0°C | 18°C |
| February | 13°C | 16.0°C | 19°C |
| March | 13°C | 16.0°C | 19°C |
| April | 12°C | 15.0°C | 18°C |
| May | 11°C | 13.0°C | 15°C |
| June | 10°C | 12.0°C | 14°C |
| July | 9°C | 11.0°C | 13°C |
| August | 9°C | 11.0°C | 12°C |
| September | 10°C | 11.0°C | 12°C |
| October | 10°C | 12.0°C | 14°C |
| November | 10°C | 13.0°C | 15°C |
| December | 12°C | 15.0°C | 17°C |
Foveaux Strait, between the South Island and Stewart Island, is influenced by cooler southern waters for much of the year. Summer sea temperatures typically reach around 14–17°C, while winter can see them hover near 9–12°C. The seasonal range is narrower than in northern New Zealand, and even at its warmest the water remains on the cooler side. Frequent winds and tidal movement help keep temperatures relatively stable but fresh.
Swimming Conditions
Swimming in Foveaux Strait is generally a bracing experience. During the height of summer, confident swimmers may enjoy short dips, especially on calm days, but it rarely feels truly warm. For much of the year, the combination of cool water and exposed conditions means a wetsuit is strongly recommended. The rugged southern setting is stunning, but anyone heading in for a swim should be prepared for proper southern-chilled water.