Whanganui River – current water temperature and swimming conditions

This page provides information about the current water temperature at Whanganui River in Manawatū–Whanganui. Here you can view recent temperature trends on a 30-day chart, check typical monthly water temperature ranges, and compare today’s reading with historical averages for this date. A 7-day water temperature forecast, local weather conditions, and an overview of swimming suitability are also included.

Current Water Temperature

13.9°C

Today

14.2°C

Yesterday

15.9°C

A Week Ago

The water temperature in Whanganui River today is 14°C.

Water Temperature in Whanganui River: Daily Trends, Historical Records, and Forecast

⚠️ River water between 10 and 15°C is cold but manageable for short swims, especially on sunny days with warm air temperatures. The moving nature of a river can make the water feel colder than the actual reading, particularly in shaded or deeper sections. Casual swimming is usually brief, with wetsuits often preferred. Windy or cool weather can significantly reduce comfort, even when the air temperature is mild.

Water Temperature Over the Last 30 Days

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

According to our forecast, the water temperature in Whanganui River will be 12.3°C in the next 7 days. See the table below for daily data for the upcoming week.

Table of Daily Water Temperature Data

Date	Current	Average	Forecast
May 6	14.1°C	12.1°C
May 7	14.1°C	12.1°C
May 8	15.9°C	12.1°C
May 9	16.0°C	12.1°C
May 10	16.1°C	12.1°C
May 11	16.1°C	12.1°C
May 12	15.9°C	12.1°C
May 13	14.2°C	12.1°C
May 14	13.9°C	12.1°C	13.9°C
May 15		12.1°C	13.7°C
May 16		12.1°C	13.5°C
May 17		12.1°C	13.2°C
May 18		12.1°C	13.0°C
May 19		12.1°C	12.8°C
May 20		12.1°C	12.6°C
May 21		12.1°C	12.3°C

* Current - Actual water temperature value

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

*** Forecast - Our water temperature forecast

Actual river water temperatures may vary by several degrees from the reported values, particularly after heavy rainfall or periods of changing weather. Rainfall, river flow rates, and runoff from cooler upstream areas can significantly affect water temperature, especially in flowing sections and shaded stretches. Air temperature and cloud cover also play an important role, with warm, sunny conditions helping rivers warm up more quickly. As a result, noticeable temperature differences can occur along the same river.

Our forecast is based on a proprietary mathematical model that takes into account real-time river temperature changes, historical data, seasonal patterns, river flow conditions, recent rainfall, and local air temperature. We also factor in broader weather conditions specific to each region of New Zealand to improve accuracy.

Monthly Water Temperature Range (Min, Max & Average)

Month	Today	Yesterday	A Week Ago
January	17°C	22°C	27°C
February	13°C	20°C	27°C
March	13°C	19°C	24°C
April	10°C	15°C	19°C
May	8°C	12°C	16°C
June	4°C	9°C	14°C
July	4°C	9°C	13°C
August	6°C	10°C	13°C
September	8°C	12°C	16°C
October	10°C	15°C	19°C
November	11°C	17°C	23°C
December	14°C	20°C	25°C

Whanganui River: Water Temperature by Location

🔗 Whanganui

Manawatū–Whanganui

14.0°C

🔗 Taumarunui

Manawatū–Whanganui

13.3°C

Whanganui River: Weather Forecast

May 15

3°C / 16°C

overcast

rain: 0% | wind: 10 km/h

May 16

2°C / 15°C

clear sky

rain: 0% | wind: 12 km/h

May 17

0°C / 15°C

overcast

rain: 0% | wind: 14 km/h

May 18

1°C / 16°C

overcast

rain: 0% | wind: 4 km/h

May 19

0°C / 17°C

overcast

rain: 0% | wind: 7 km/h

Location & Local Information

Source Mount Tongariro Mouth Tasman Sea • coordinates 39°56.89′S 174°59.22′E • elevation Sea level Length 290 km (180 mi)

The Whanganui River is one of New Zealand’s longest navigable rivers and a defining feature of the Manawatū–Whanganui, flowing from the central plateau to the Tasman Sea. Water temperatures vary along its length and through the seasons, influenced by altitude, rainfall, and river flow. In summer, temperatures typically sit around 17–21 °C, feeling comfortable in slower, sun-exposed reaches. Spring and autumn usually bring cooler conditions of about 13–17 °C. In winter, the river cools noticeably, often dropping to roughly 9–12 °C, which feels cold and limits time in the water.

Swimming Conditions

Swimming in the Whanganui River is allowed and enjoyed in many areas, particularly during summer when temperatures are at their warmest. Calm sections near riverbanks, beaches, and recognised access points are commonly used for swimming and cooling off on hot days. The river’s character changes along its course, with some stretches slow and wide, while others are narrower with stronger currents. After heavy rain, water levels can rise quickly and clarity can reduce, affecting swimming conditions. For these reasons, swimming is best suited to settled summer weather and well-known locations. Outside the warmer months, cooler temperatures and increased flow make swimming less appealing for most people. Overall, the Whanganui River offers good seasonal swimming opportunities, especially in summer, alongside its wider recreational and cultural importance.

Nearby Rivers

Frequently Asked Questions

What is the current water temperature in Whanganui River?

The water temperature in Whanganui River today is 14°C.

What is the water temperature in Whanganui River during the summer months?

In summer, water temperatures in Whanganui River at Wangi Wangi typically range from 13°C to 27°C.

Is it possible to swim in Whanganui River (Manawatū–Whanganui)?

Yes — you can swim in calmer, sheltered sections of the Whanganui River, particularly in summer, but conditions vary along its length and there can be strong currents, submerged hazards and fluctuating water quality. The water tends to be cool year‑round, so check local signage and current water‑quality advisories before entering and consider a wetsuit or lifejacket if you’re unsure.