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Joetsu Sea Temperature in September

Japan

August Joetsu year-round → October

Average sea temperature for Joetsu, Japan across September, based on 10 years of daily readings.

Average

26.2° C

High

29.05° C

Low

22.99° C

This water temperature is comparable to that of a swimming pool, but it might be higher than most open water swimmers prefer for serious swimming. Make sure to drink plenty of water before and after swimming and don't wear a wetsuit to avoid overheating.

September is the 2nd warmest of 12 months at Joetsu. On average the water sits 7.9° than the year-round mean of 18.26° C.

Compared to August, September is 1.5° cooler than (27.67° C in August). By October the water is usually 22.65° C.

Joetsu Day-by-Day Water Temperature in September

10-year low, average and high

22.0° C
24.0° C
26.0° C
28.0° C
30.0° C
1
5
10
15
20
25
30
Day-by-day low and high band with the 10-year daily average through September. Range Average

Each vertical bar above is one day of September. The shaded band covers the range the water has reached on that day across the last 10 years — the lowest reading at the bottom, the highest at the top. The line running through the bars is the daily average over those 10 years, so you can see the typical shape of the month at Joetsu.

A narrow band means the temperature on that day has stayed close to the average year on year. A taller band means it has swung more, often because of changeable weather around that time of year. Hovering a day pulls up its low, average, and high.

September Water Temperature Table for Joetsu

10-year daily averages

Day Average Low High
September 1 27.15° C 25.31° C 29.05° C
September 2 27.08° C 24.85° C 28.92° C
September 3 26.97° C 24.85° C 28.82° C
September 4 26.96° C 25.21° C 28.83° C
September 5 27.05° C 24.65° C 28.77° C
September 6 27.1° C 24.64° C 28.63° C
September 7 27.09° C 24.65° C 28.47° C
September 8 26.88° C 24.61° C 28.39° C
September 9 26.78° C 24.28° C 28.47° C
September 10 26.86° C 24.63° C 28.39° C
September 11 26.85° C 24.61° C 28.37° C
September 12 26.68° C 24.45° C 28.3° C
September 13 26.53° C 24.08° C 28.34° C
September 14 26.44° C 23.83° C 28.41° C
September 15 26.43° C 24.28° C 28.2° C
September 16 26.46° C 24.55° C 28.29° C
September 17 26.28° C 24.44° C 28.42° C
September 18 26.13° C 24.27° C 28.41° C
September 19 26.05° C 24.27° C 28.4° C
September 20 25.94° C 24.17° C 28.38° C
September 21 25.67° C 23.95° C 27.84° C
September 22 25.63° C 23.65° C 27.67° C
September 23 25.48° C 23.58° C 27.36° C
September 24 25.43° C 23.66° C 27.19° C
September 25 25.32° C 23.73° C 27.1° C
September 26 25.18° C 23.67° C 27.01° C
September 27 25.07° C 23.33° C 26.86° C
September 28 24.96° C 23.37° C 26.63° C
September 29 24.86° C 23.38° C 26.52° C
September 30 24.73° C 22.99° C 26.44° C

Where September Sits in the Year

September highlighted

7.0° C
13.4° C
19.8° C
26.1° C
32.5° C
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
13.07° C
11.29° C
10.63° C
12.01° C
15.55° C
20.28° C
24.97° C
27.67° C
26.2° C
22.65° C
18.87° C
15.88° C
10-year monthly history for Joetsu. Bars span historical low to high; the line marks the monthly average. Range Average
January → February → March → April → May → June → July → August → September → October → November → December →

Nearby Locations in September

Compare other Japan water for the same month

Joetsu Location

37.1479, 138.2361

37.14790, 138.23613 View on OpenStreetMap →

Joetsu sits at 37.1479°N, 138.2361°E, on the coast of Japan. The marker on the map shows the spot the readings on this page come from. It usually sits a short distance from the town centre, out on the open water itself, so the numbers stay tied to the coast rather than a generic point inland.

Coastlines bend, headlands focus the water, and the temperature can run noticeably differently between two beaches that look close together on a map. Comparing nearby locations is a quick way to see how local geography is shaping the readings.

Nearest locations to Joetsu