Kai Iwi Beach – current water temperature and swimming conditions

This page shows the current water temperature at Kai Iwi Beach in Manawatū–Whanganui. 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

13.8°C

Today

13.7°C

Yesterday

14.0°C

A Week Ago

The average sea water temperature today in Kai Iwi Beach is about 14°C.

Water Temperature in Kai Iwi Beach: Daily Trends, Historical Records, and Forecast

❌ Water at this temperature feels cold and is generally suitable only for brief immersion. Swimming without a wetsuit can quickly become uncomfortable, and exposure time is usually short. These conditions are mainly suitable for experienced swimmers or those using proper thermal gear.

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 June 10 to July 10

Water temperatures in Kai Iwi Beachfell over the past month, but have levelled out during the last week.

According to our forecast, Sea water temperature in Kai Iwi Beach will be 13.8°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
Jul 2	14.1°C	14.0°C
Jul 3	14.0°C	14.0°C
Jul 4	14.0°C	14.0°C
Jul 5	13.9°C	14.0°C
Jul 6	13.8°C	14.0°C
Jul 7	13.8°C	14.0°C
Jul 8	13.8°C	14.0°C
Jul 9	13.7°C	14.0°C
Jul 10	13.8°C	14.0°C	13.8°C
Jul 11		13.8°C	13.8°C
Jul 12		13.5°C	13.8°C
Jul 13		14.0°C	13.8°C
Jul 14		13.8°C	13.8°C
Jul 15		13.5°C	13.8°C
Jul 16		13.8°C	13.8°C
Jul 17		13.5°C	13.8°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 Kai Iwi Beach 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

Kai Iwi Beach, just north of Whanganui in the Manawatū–Whanganui region, faces west toward Cook Strait and the Tasman-influenced waters along this coast. Sea temperatures here follow a typical lower North Island cycle. 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 swimmers or those wearing full wetsuits. Through spring, temperatures gradually lift 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 weather. 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	15°C	18°C	21°C
February	17°C	19°C	21°C
March	15°C	18°C	21°C
April	16°C	18°C	19°C
May	14°C	16°C	19°C
June	12°C	15°C	17°C
July	11°C	14°C	16°C
August	11°C	13°C	15°C
September	11°C	13°C	15°C
October	11°C	14°C	16°C
November	13°C	15°C	19°C
December	14°C	17°C	20°C

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

Kai Iwi Beach: Weather Forecast

July 11

2°C / 10°C

clear sky

humidity: 76% | wind: 7 kmh

July 12

4°C / 11°C

clear sky

humidity: 74% | wind: 4 kmh

July 13

11°C / 14°C

overcast clouds: 85-100%

humidity: 70% | wind: 14 kmh

Local Water Conditions and Nearby Spots

Swimming Conditions

Swimming is allowed at Kai Iwi Beach and it’s a well-known local spot during the warmer months. The beach is wide and sandy, offering plenty of space, but it remains an open and energetic west coast environment. Swells, rip currents and shifting sandbars can develop depending on wind and tide. In peak summer there are often lifeguard patrols, and swimming between the flags is strongly recommended. On calm, sunny days the water can be refreshing and enjoyable for confident swimmers and families alike. Outside the warmer season, cooler water temperatures and more active surf make thermal gear advisable. When conditions are settled, Kai Iwi Beach provides a classic west coast ocean swimming experience.