Ōkiwi Bay – current water temperature and swimming conditions

This page shows the current water temperature at Ōkiwi Bay in Marlborough Region. You can view recent sea temperature trends on a 30-day chart, check typical monthly water temperature ranges, and compare today’s reading with historical averages for this date. The page also includes a 7-day water temperature forecast, nearby beaches with similar conditions, local weather information, and a summary of swimming conditions to help you assess how suitable the water is for swimming.

Current Sea Water Temperature

16.0°C

Today

16.1°C

Yesterday

16.5°C

A Week Ago

The average sea water temperature today in Ōkiwi Bay is about 16°C.

Water Temperature in Ōkiwi 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

From April 14 to May 14

Water temperatures in Ōkiwi Bay 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 Ōkiwi Bay will be 14.3°C in the next 7 days. See the table below for daily data for the upcoming week.

Table of Daily Sea Temperature Data

Date	Current	Average	Forecast
May 7	16.4°C	14.8°C
May 8	16.4°C	14.8°C
May 9	16.5°C	15.0°C
May 10	16.6°C	14.8°C
May 11	16.5°C	14.8°C
May 12	16.5°C	15.3°C
May 13	16.5°C	14.5°C
May 14	16.1°C	14.8°C
May 15	16.0°C	14.8°C	16.0°C
May 16		13.0°C	15.8°C
May 17		13.8°C	15.5°C
May 18		14.0°C	15.3°C
May 19		13.3°C	15.0°C
May 20		13.5°C	14.8°C
May 21		13.5°C	14.5°C
May 22		14.3°C	14.3°C

* Current - Actual water temperature value

** Average - Average water temperature on this day in recent years

*** Forecast - Our water temperature forecast

Actual near-shore water temperatures in Ōkiwi Bay can vary by several degrees from the values shown, particularly after heavy rain, strong southerlies, or prolonged windy conditions. Certain wind patterns can trigger upwelling, where cooler, deeper water is pushed to the surface and replaces the warmer top layer, leading to noticeable short-term changes in water temperature.

Our water temperature forecast is produced using a proprietary mathematical model that combines real-time measurements with long-term historical patterns, local weather conditions, wind strength and direction, and air temperature specific to each coastal region. To improve accuracy, we cross-check data from nearby locations and use multiple sources, including offshore buoys, satellite-based sea surface maps, and observations provided by local authorities.

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

Ōkiwi Bay is a small, sheltered coastal settlement in the Marlborough Region, opening into the outer reaches of Queen Charlotte Sound and influenced by Cook Strait. Water temperatures here reflect the cool, tidal nature of the region, though the bay’s shape offers more protection than fully exposed coastline. In winter, from June to August, the water generally ranges between 9–12°C, which feels properly cold and is usually only comfortable for hardy swimmers or those wearing full wetsuits. Through spring, temperatures gradually lift to around 11–14°C. Summer, from December to March, brings the mildest conditions, with water temperatures commonly sitting between 16–19°C during settled spells. Early autumn can still see 15–17°C before cooling again as winter approaches.

Monthly Water Temperature Range (Min, Max & Average)

Month	Min	Avg	Max
January	14°C	16°C	19°C
February	14°C	17°C	19°C
March	14°C	16°C	19°C
April	12°C	15°C	17°C
May	11°C	14°C	17°C
June	10°C	13°C	16°C
July	10°C	12°C	15°C
August	9°C	12°C	14°C
September	10°C	12°C	14°C
October	10°C	13°C	15°C
November	11°C	14°C	16°C
December	13°C	15°C	18°C

* Click on a month to view detailed water temperature data.

Ōkiwi Bay: Weather Forecast

May 15

8°C / 14°C

overcast clouds: 85-100%

humidity: 80% | wind: 7 kmh

May 16

6°C / 11°C

overcast clouds: 85-100%

humidity: 78% | wind: 7 kmh

May 17

5°C / 13°C

clear sky

humidity: 85% | wind: 4 kmh

May 18

5°C / 14°C

clear sky

humidity: 83% | wind: 0 kmh

Local Water Conditions and Nearby Spots

Swimming Conditions

Swimming is allowed at Ōkiwi Bay and it’s a popular local spot during the warmer months. The bay is relatively enclosed, which often means calmer water and minimal surf compared to open Cook Strait beaches. This makes it suitable for families and casual swimmers on fine days. However, tidal movement and occasional wind chop can influence conditions, and there are generally no regular lifeguard patrols. Swimmers should assess the water carefully before entering. On warm summer days, the clearer and slightly milder water can be refreshing and enjoyable. Outside the warmer season, thermal gear is recommended, as the water remains cool year-round despite the sheltered setting.