Whanganui – current water temperature and swimming conditions

Water Temperature in Whanganui: 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

Water temperatures in Whanganui have been gradually cooling over the past month, with a further drop recorded during the last week.

According to our forecast, Sea water temperature in Whanganui will be 16.0°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

Whanganui sits on the lower west coast of the North Island in the Manawatū–Whanganui region, where the Whanganui River meets the sea near Cook Strait and the Tasman-influenced coastline. Sea temperatures here follow a clear seasonal pattern. In winter, from June to August, the water generally ranges between 10–13°C, which feels properly cold and is usually only comfortable for hardy swimmers or those in full wetsuits. Through spring, temperatures gradually rise to around 13–15°C. Summer, from December to March, brings the most inviting conditions, with sea temperatures commonly sitting between 16–19°C during settled spells. Early autumn can still see 15–17°C before cooling again as winter approaches.