Water temperature in Sumner in September

Is it warm enough to swim in Sumner in September? Average water temperature in Sumner in September is 10.2°C and therefore is not suitable for comfortable swimming. The warmest sea in Sumner in September is 11.7°C, and the coldest is 8.2°C. To find out the sea temperature today and in the coming days, go to Current sea temperature in Sumner

Changes water temperature in Sumner in September 2025, 2024

To get an accurate forecast for the water temperature in Sumner for any chosen month, compare two years within a 10 year range using the chart below. In addition to the sea water temperature in Sumner, the selected years in the table also show the values of the maximum and minimum temperatures on each of the days of September.

Sea temperature

Tides

Weather forecast

You can choose any other years:

Day	2025	2024	Min	Max
1 September	9.6°C	10°C	8.7°C	10.1°C
2 September	9.6°C	10.2°C	8.6°C	10.7°C
3 September	9.7°C	10.2°C	8.5°C	10.8°C
4 September	10°C	10.1°C	8.7°C	10.7°C
5 September		10.3°C	8.6°C	10.5°C
6 September		10.2°C	8.5°C	10.7°C
7 September		10.6°C	8.2°C	10.8°C
8 September		10.5°C	8.3°C	11.3°C
9 September		10.6°C	8.8°C	11.1°C
10 September		10.4°C	8.4°C	11°C
11 September		10.8°C	8.5°C	11.1°C
12 September		10.8°C	8.6°C	11.3°C
13 September		10.8°C	8.7°C	11.2°C
14 September		10.5°C	8.8°C	11.1°C
15 September		10.6°C	9.1°C	10.9°C

Day	2024	Min	Max
16 September	10.5°C	9.3°C	11.2°C
17 September	10.5°C	9.3°C	11.1°C
18 September	10.2°C	9.5°C	11.6°C
19 September	10°C	9.2°C	11.5°C
20 September	10.5°C	9.3°C	11.4°C
21 September	11.3°C	9.2°C	11.7°C
22 September	10.8°C	9.3°C	11.6°C
23 September	11.1°C	9.5°C	11.4°C
24 September	11.1°C	9.4°C	11.5°C
25 September	10.9°C	9.4°C	11.6°C
26 September	10.8°C	9.5°C	11.5°C
27 September	10.9°C	9.8°C	11.3°C
28 September	11.1°C	9.9°C	11.3°C
29 September	11.3°C	10.1°C	11.3°C
30 September	11°C	10.1°C	11.6°C

Average water temperature in Sumner in September over a decade

2015	2016	2017	2018	2019
9.1°C	10.2°C	10.3°C	10.4°C	10.2°C

2020	2021	2022	2023	2024
10.6°C	10.4°C	10.6°C	11°C	10.6°C

Sumner sea state in September

Chart comparing the height of waves in Sumner in September over the past years. The red line indicates the height of the waves when swimming in the sea is prohibited. To view the current sea conditions, click on the graph.

Sumner water temperature during other months:

You can also view information about water temperature for other months by clicking on the month button below

Temperature in neighboring cities

The nearest locations with the average water temperature in September. In addition, the maximum and minimum water temperatures for that month, recorded over the last decade, are shown

	Avr	Min	Max
Taylors Mistake	10.2°C	8.2°C	11.7°C
Corsair Bay	10.1°C	8.2°C	11.9°C
New Brighton	10.1°C	8.2°C	11.6°C
Waikuku	10.1°C	8.2°C	11.5°C
Kaikoura	10.5°C	9.1°C	12°C
Punakaiki	12.8°C	11.7°C	14.3°C
Oamaru	10.1°C	8.6°C	11.8°C
Westport	12.8°C	11.5°C	14.3°C
Mapua	12.4°C	10.9°C	13.8°C
Wellington	11.7°C	10.3°C	13.4°C

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Our report for Sumner is compiled using satellite data together with in-situ observations to get the most reliable daily data of sea surface temperatures, surf forecasts, current temperatures and weather forecasts.

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Date (day and month)

Water temperature: min 16°C

Average temperature Maximum temperature