Masterton – current water temperature and swimming conditions

This page provides information about the current water temperature at Masterton in Wellington Region. 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

12.2°C

Today

12.8°C

Yesterday

14.5°C

A Week Ago

The water temperature in Ruamāhanga River at Masterton today is 12°C.

Water Temperature in Ruamāhanga River at Masterton: 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 Masterton 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 Masterton will be 11.2°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	12.4°C	11.0°C
May 7	12.4°C	11.0°C
May 8	14.5°C	11.0°C
May 9	14.5°C	11.0°C
May 10	14.6°C	11.0°C
May 11	14.6°C	11.0°C
May 12	14.4°C	11.0°C
May 13	12.8°C	11.0°C
May 14	12.2°C	11.0°C	12.2°C
May 15		11.0°C	12.1°C
May 16		11.0°C	11.9°C
May 17		11.0°C	11.8°C
May 18		11.0°C	11.6°C
May 19		11.0°C	11.5°C
May 20		11.0°C	11.3°C
May 21		11.0°C	11.2°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	15°C	20°C	25°C
February	14°C	20°C	25°C
March	12°C	18°C	23°C
April	9°C	14°C	19°C
May	7°C	11°C	15°C
June	6°C	10°C	14°C
July	5°C	8°C	11°C
August	6°C	10°C	13°C
September	6°C	12°C	17°C
October	7°C	13°C	18°C
November	9°C	16°C	23°C
December	11°C	17°C	22°C

Masterton: Weather Forecast

May 15

9°C / 13°C

light drizzle

rain: 4% | wind: 11 km/h

May 16

8°C / 12°C

light drizzle

rain: 29% | wind: 11 km/h

May 17

5°C / 12°C

overcast

rain: 32% | wind: 10 km/h

May 18

4°C / 12°C

partly cloudy

rain: 6% | wind: 7 km/h

May 19

3°C / 13°C

overcast

rain: 0% | wind: 7 km/h

May 20

4°C / 15°C

overcast

rain: 6% | wind: 7 km/h

Location & Local Information

Masterton, located in the Wairarapa of the Wellington Region, sits close to the middle reaches of the Ruamāhanga River. In this lowland section, water temperatures reflect seasonal air conditions rather than alpine snowmelt. During winter, the river near Masterton is generally cool, with temperatures around 8–12°C. In spring, readings typically rise to between 12 and 16°C as days become milder. Over summer, especially in January and February, calmer pools and wider stretches can warm to approximately 18–23°C on settled, sunny days. By autumn, temperatures usually ease back to around 13–17°C. Heavy rainfall in the Tararua Ranges can temporarily lower temperatures and increase river flow.

Swimming Conditions

Swimming is allowed in suitable parts of the Ruamāhanga River near Masterton, and locals often visit established swimming spots during the warmer months. The most comfortable conditions are generally in mid to late summer when water temperatures approach or exceed 18°C and river levels are steady. However, swimmers should be aware of changing depths, submerged debris and moderate currents in some sections. It is advisable to avoid entering the river after significant rainfall, when flows can rise quickly and water clarity may decrease. Checking regional water quality information before swimming is recommended to ensure safe conditions.

Nearby Places

Frequently Asked Questions

What is the current water temperature in Ruamāhanga River at Masterton?

The water temperature in Ruamāhanga River at Masterton today is 12°C.

What is the water temperature in Ruamāhanga River at Masterton during the summer months?

In summer, water temperatures in Ruamāhanga River at Masterton at Wangi Wangi typically range from 11°C to 25°C.

Is it possible to swim in Ruamāhanga River at Masterton (Wellington Region)?

Yes — there are calmer, shallow stretches of the Ruamāhanga near Masterton that people do swim in during the warmer months, though the water can be quite cool outside mid‑summer. Always check local signage and recent water‑quality or flood warnings from Masterton District Council or Greater Wellington Regional Council, avoid swimming after heavy rain, and be mindful of strong currents, submerged hazards and potential algal blooms.