Selwyn River – current water temperature and swimming conditions

This page provides information about the current water temperature at Selwyn River in Canterbury 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

12.3°C

Today

12.2°C

Yesterday

10.9°C

A Week Ago

The water temperature in Selwyn River today is 12°C.

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

According to our forecast, the water temperature in Selwyn River will be 11.6°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
Oct 8	11.2°C	11.5°C
Oct 9	11.5°C	11.5°C
Oct 10	10.9°C	11.5°C
Oct 11	11.5°C	11.5°C
Oct 12	11.6°C	11.5°C
Oct 13	11.2°C	11.5°C
Oct 14	11.6°C	11.5°C
Oct 15	12.2°C	11.5°C
Oct 16	12.3°C	11.5°C	12.3°C
Oct 17		11.5°C	12.2°C
Oct 18		11.5°C	12.1°C
Oct 19		11.5°C	12.0°C
Oct 20		11.5°C	11.9°C
Oct 21		11.5°C	11.8°C
Oct 22		11.5°C	11.7°C
Oct 23		11.5°C	11.6°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	14°C	16°C	18°C
February	9°C	14°C	19°C
March	12°C	15°C	18°C
April	8°C	13°C	17°C
May	6°C	9°C	11°C
June	3°C	7°C	10°C
July	3°C	7°C	10°C
August	3°C	6°C	9°C
September	5°C	9°C	12°C
October	8°C	12°C	15°C
November	10°C	14°C	18°C
December	13°C	15°C	16°C

Selwyn River: Weather Forecast

October 17

2°C / 17°C

fog

rain: 0% | wind: 11 km/h

October 18

7°C / 19°C

fog

rain: 0% | wind: 12 km/h

October 19

8°C / 21°C

mainly clear

rain: 6% | wind: 16 km/h

October 20

8°C / 21°C

clear sky

rain: 10% | wind: 18 km/h

October 21

9°C / 21°C

clear sky

rain: 15% | wind: 10 km/h

Location & Local Information

Source: • location Southern Alps Mouth: • location Lake Ellesmere / Te Waihora Length 80 km

The Selwyn River, also known as the Waikirikiri, flows across the Canterbury Plains from the foothills towards Te Waihora/Lake Ellesmere. Unlike alpine-fed rivers, the Selwyn is spring-fed in many sections and can vary significantly in flow through the year. Water temperatures reflect this lowland setting. In winter, temperatures are generally around 7–11°C. During spring, they typically rise to between 11 and 15°C. In summer, especially in deeper pools and flowing sections that remain connected, water temperatures can reach approximately 16–22°C on hot Canterbury days. By autumn, temperatures usually ease back to around 10–16°C. Extended dry periods may reduce flow in some reaches, which can influence both temperature and water quality.

Swimming Conditions

Swimming is allowed in parts of the Selwyn River when there is sufficient flow, and some sections are used recreationally during the warmer months. The most comfortable conditions are usually in mid to late summer when temperatures approach or exceed 18°C and the river is flowing steadily. However, swimmers should be aware that the Selwyn can have variable depths, soft riverbeds and occasional strong currents in narrower sections. Water quality can also change after heavy rain or during low-flow periods, so checking regional updates before swimming is recommended to ensure safe conditions.

Nearby Rivers

Frequently Asked Questions

What is the current water temperature in Selwyn River?

The water temperature in Selwyn River today is 12°C.

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

In summer, water temperatures in Selwyn River at Wangi Wangi typically range from 9°C to 19°C.

Is it possible to swim in Selwyn River (Canterbury Region)?

Yes — you can swim in parts of the Selwyn River / Waikirikiri, but conditions vary a lot along its length and through the seasons, so some reaches are shallow or low-flow in summer while others may have cold water, fast currents or debris. Always check Environment Canterbury (ECan) or Selwyn District Council water‑quality and flow updates, heed local signage, avoid swimming after heavy rain and don’t swim alone.