Island Bay – current water temperature and swimming conditions

Water Temperature in Island Bay: Daily Trends, Historical Records, and Forecast

⚠️ 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.

Water Temperature Over the Last 30 Days

While water temperatures in Island Bay declined overall during the past month, they have shown a noticeable rebound over the last week.

According to our forecast, Sea water temperature in Island Bay will be 14.9°C in the next 7 days. See the table below for daily data for the upcoming week.

Table of Daily Sea Temperature Data

Annual Water Temperature Overview by Month

Monthly Water Temp Ranges

30°C

25°C

20°C

15°C

10°c

5°C

0°C

Annual Water Temperature Trend

Island Bay is a coastal suburb on Wellington’s south coast, looking out across Cook Strait toward the South Island. Sea temperatures here are shaped by strong tidal flows and frequent winds that move through the strait. In winter, from June to August, the water generally ranges between 10–13°C, which feels distinctly cold and is usually only comfortable for hardy locals or swimmers in wetsuits. Through spring, temperatures gradually lift to around 13–15°C. Summer, from December to March, brings the mildest conditions, with sea temperatures commonly sitting between 16–19°C during settled weather. Early autumn can still see 15–17°C before cooling again heading into winter.