Ranganunu Harbour – current water temperature and swimming conditions

Water Temperature in Ranganunu Harbour: 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 Ranganunu Harbour have been on a steady rise over the past month and have continued to climb over the last week.

According to our forecast, Sea water temperature in Ranganunu Harbour will be 16.3°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

Ranganunu Harbour is a sheltered inlet in the Far North of the Northland Region, connected to the Pacific Ocean but protected from the full force of open swells. Owing to its northern location, water temperatures are relatively mild by New Zealand standards. In summer, from December through February, harbour water temperatures generally range between 19°C and 22°C, and shallow areas can warm slightly more on sunny, windless days. During autumn, temperatures often remain around 18–20°C before gradually easing down. Winter usually sees water between 14°C and 16°C, while spring brings a steady warming from about 15°C towards 18°C as daylight increases and air temperatures rise.