Sea temperature in Joetsu in Japan real-time sea temperature, 7-day forecast and historical data

Temperature of the sea in Joetsu today

Currently, the sea water temperature in Joetsu is at most:

63°F

(or 5° higher than the seasonal norm)

Other useful information about today's weather:

• Outside temperature: 38°F to 45°F
• Light sleet
• The wind is blowing at 14.3mph
• Wave height is 7.5ft on average, and 1.6ft at most, with a frequency of a wave every 8.8 seconds.
• More details on the sea weather of Joetsu page

This report was generated on 05/12/2025

7 day sea water temperature forecast in Joetsu

Discover the weather forecast for the water temperature in Joetsu for the next 7 days below. You will also find the 7-day forecast for outside temperature and wave height. For more details, hour by hour, see the chart below the listing.

Friday 5 December 2025

sea temperature:
63°F

Wave height: 6.6ft to 9.8ft

Outside temperature: 38°F to 45°F

Saturday 6 December 2025

sea temperature:
63°F

Wave height: 3.3ft to 6.2ft

Outside temperature: 38°F to 43°F

Sunday 7 December 2025

sea temperature:
63°F

Wave height: 3.6ft to 7.5ft

Outside temperature: 41°F to 50°F

Monday 8 December 2025

sea temperature:
63°F

Wave height: 5.6ft to 9.5ft

Outside temperature: 47°F to 52°F

Tuesday 9 December 2025

sea temperature:
63°F

Wave height: 5.9ft to 6.6ft

Outside temperature: 43°F to 47°F

Wednesday 10 December 2025

sea temperature:
63°F

Wave height: 3.3ft to 5.6ft

Outside temperature: 40°F to 47°F

Thursday 11 December 2025

sea temperature:
63°F

Wave height: 2.6ft to 4.9ft

Outside temperature: 43°F to 50°F

Chart of water temperature variation over 7 days

History of water temperature in Joetsu

We record the water temperature daily in Joetsu In this way, we can provide you with the average sea temperature in Joetsu over the last 24 months and a more detailed chart for recent months.

Monthly sea temperature averages over 24 months

december 2025

Average water temperature: 63°F (63°F)

november 2025

Average water temperature: 66°F (63°F to 70°F)

october 2025

Average water temperature: 76°F (70°F to 80°F)

september 2025

Average water temperature: 82°F (79°F to 85°F)

august 2025

Average water temperature: 83°F (79°F to 86°F)

july 2025

Average water temperature: 75°F (68°F to 83°F)

june 2025

Average water temperature: 65°F (59°F to 68°F)

may 2025

Average water temperature: 55°F (50°F to 61°F)

april 2025

Average water temperature: 50°F (47°F to 54°F)

march 2025

Average water temperature: 50°F (47°F to 52°F)

february 2025

Average water temperature: 53°F (52°F to 54°F)

january 2025

Average water temperature: 56°F (54°F to 58°F)

december 2024

Average water temperature: 61°F (58°F to 63°F)

november 2024

Average water temperature: 66°F (63°F to 68°F)

october 2024

Average water temperature: 75°F (70°F to 79°F)

september 2024

Average water temperature: 81°F (77°F to 83°F)

august 2024

Average water temperature: 81°F (76°F to 85°F)

july 2024

Average water temperature: 72°F (70°F to 76°F)

june 2024

Average water temperature: 66°F (59°F to 70°F)

may 2024

Average water temperature: 58°F (52°F to 63°F)

april 2024

Average water temperature: 50°F (47°F to 56°F)

march 2024

Average water temperature: 50°F (47°F to 52°F)

february 2024

Average water temperature: 52°F (49°F to 52°F)

january 2024

Average water temperature: 56°F (54°F to 58°F)

Variation of water temperature in Joetsu over the past 2 months