Surf Forecasts:
Keta Reef Oshima surf forecast from 17 Sep 2026:
- Best quality surf: Monday 21 Sep, 9PM (local time) - 2.5ft (0.7m), 10s period, SSE swell with offshore winds.
- Most powerful swell: Monday 21 Sep, 3AM (local time) - 15ft (4.5m), 13s period, SE swell with 6,997 kJ wave energy.
- Next surfable swell (1★+): Monday 21 Sep, 9PM (local time) - 2.5ft (0.7m), 10s period with SSE swell.
Best Forecast Surf Conditions for Keta Reef Oshima this week:
The surf forecast for Keta Reef Oshima over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Monday (Sep 21) at 9PM. The primary swell is predicted to be 0.7m and 10s period with a secondary swell of 0.7m and 10s. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Keta Reef Oshima in the next 16 days are 4.5m 13s and forecast to arrive on Monday (Sep 21) at 3AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 2.4m 6s period and expected on Sunday (Sep 20) at 6PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9PM (Mon 21st Sep) | 2.5ft (0.7m) 10s |
| Best Surf | 9PM (Mon 21st Sep) | 2.5ft (0.7m) 10s |
| Most Powerful | 3AM (Mon 21st Sep) | 15ft (4.5m) 13s |
Table - best surf conditions forecast for Keta Reef Oshima over the next 16 days.
Short Range ForecastHeavy rain (total 110mm), heaviest during Sun afternoon. Warm (max 24°C on Sat afternoon, min 20°C on Thu night). Winds increasing (strong winds from the NNE on Sat afternoon, gales from the N by Sun afternoon). | Days 5-7 Weather SummaryHeavy rain (total 133mm), heaviest during Sun night. Warm (max 27°C on Mon morning, min 22°C on Tue afternoon). Winds decreasing (stormy winds from the N on Sun night, light winds from the S by Mon afternoon). | ||||||||||||||||||
Friday 18 | Saturday 19 | Sunday 20 | Monday 21 | Tuesday 22 | Wednesday 23 | ||||||||||||||
Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | |
Swell Height Map |  |  |  |  |  |  |  | ||||||||||||
Wave Height (m) Direction Period (s) | ENE 11 | ENE 12 | E 11 | SE 14 | SE 15 | SE 13 | SE 12 | SE 12 | SE 12 | SE 13 | SE 12 | SSE 11 | SSE 9 | SSE 8 | SE 8 | ESE 6 | ESE 7 | E 6 | E 9 |
Wave Graph  | |||||||||||||||||||
 kJ | 37 | 46 | 12 | 596 | 4223 | 3160 | 2302 | 3368 | 4180 | 6180 | 1655 | 311 | 59 | 28 | 30 | 36 | 70 | 75 | 7 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | on | cross | cross-off | cross-off | off | cross-off | cross-off | cross-off | cross-off |
High Tide | 9:52AM1.12m | 7:22PM1.38m | 7:43PM1.30m | 4:18PM1.20m | 8:03PM1.20m | 3:19PM1.26m | 00:08AM1.16m | 3:30PM1.32m | 1:44AM1.24m | 3:46PM1.37m | 2:39AM1.34m | ||||||||
Low Tide | 2:30AM0.44m | 1:30PM1.05m | 3:28AM0.52m | 5:07AM0.57m | 5:55PM1.20m | 6:55AM0.54m | 8:28PM1.10m | 8:00AM0.47m | 8:52PM0.98m | 8:45AM0.40m | 9:17PM0.86m | ||||||||
 |  | | |  | |  |  | | | |  |  | | |  |  | | | |
 | — | 5:26 | — | — | 5:26 | — | — | 5:28 | — | — | 5:28 | — | — | 5:28 | — | — | 5:30 | — | — |
 | — | — | 5:45 | — | — | 5:45 | — | — | 5:43 | — | — | 5:42 | — | — | 5:39 | — | — | 5:38 | — |
mm | — | — | — | — | — | — | 15 | 39 | 56 | 130 | — | — | — | — | — | 2 | 1 | — | 1 |
Temp °C | 21 | 21 | 22 | 22 | 22 | 24 | 24 | 23 | 23 | 26 | 27 | 27 | 27 | 24 | 24 | 23 | 22 | 23 | 23 |
Feels °C | 14 | 12 | 14 | 15 | 15 | 19 | 19 | 15 | 14 | 18 | 29 | 29 | 28 | 21 | 20 | 20 | 19 | 20 | 21 |
Swell 1 Height (m) Direction Period (s) | ENE 11 | ENE 12 | E 11 | SE 14 | SE 15 | SE 13 | SE 12 | SE 12 | SE 12 | SE 13 | SE 12 | E 10 | SSE 9 | SSE 8 | SE 8 | ESE 6 | ESE 7 | E 9 | E 9 |
| kJ | 37 | 46 | 10 | 596 | 4223 | 3160 | 2302 | 3368 | 4180 | 6180 | 1655 | 284 | 59 | 28 | 30 | 36 | 70 | 7 | 7 |
Swell 2 Height (m) Direction Period (s) | SE 9 | SE 12 | SSE 11 | E 9 | ENE 8 | — | — | — | N 6 | — | E 11 | SSE 11 | ESE 9 | ESE 8 | E 9 | SSE 7 | E 8 | S 8 | SSE 8 |
| kJ | 3 | 6 | 12 | 43 | 55 | — | — | — | 64 | — | 670 | 311 | 54 | 26 | 15 | 11 | 13 | 5 | 7 |
Swell 3 Height (m) Direction Period (s) | SSE 9 | S 9 | — | S 22 | — | — | — | — | E 13 | — | NNE 5 | SW 7 | WSW 7 | E 9 | SSW 5 | E 9 | SSW 8 | SE 9 | S 8 |
| kJ | 7 | 1 | — | 9 | — | — | — | — | 14 | — | 9 | 12 | 5 | 15 | 3 | 6 | 7 | 3 | 5 |
Wind waves Height (m) Direction Period (s) | NE 6 | NE 6 | NE 6 | NNE 6 | NE 6 | NE 5 | NE 5 | NNE 6 | NNE 6 | N 6 | WSW 7 | — | ENE 4 | NE 4 | ENE 5 | NE 3 | NE 4 | E 6 | E 6 |
| kJ | 234 | 302 | 309 | 227 | 193 | 94 | 68 | 217 | 408 | 333 | 73 | — | 40 | 29 | 29 | 5 | 19 | 75 | 69 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 436 | 436 | 457 | 198 | 470 | 475 | 454 | 516 | 474 | 470 | 40 | 79 | 47 | 47 | 191 | 47 | 47 | 47 | 107 |
Best forecast wave conditions in Izu Islands | |||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||
Header Global | |||||||||||||||||||
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Information about the Keta Reef Oshima Surf forecast
The above surf forecast table for Keta Reef Oshima provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Keta Reef Oshima can be found by selecting the local surf guide option on the grey menu. Our Keta Reef Oshima surf forecast is unique since it includes wave energy (power) that defines the real feel of the surf rather than just the height or the period. If you surf the same spot (Keta Reef Oshima) regularly then make a mental note of the wave energy from the surf forecast table each time you go. Very soon you may start to choose your surf days based on the wave energy alone combined with our forecast of favourable offshore wind conditions. Our star ratings will help here and of course you will also find the usual wave height and period predictions on our surf forecasts as well as a full break down of the swell components under our advanced users option (to reveal that, click the little Einstein character under the tide times).
Further information to help with frequently asked questions about our surf forecast for Keta Reef Oshima may be found under the help tab on the top menu and also by moving your mouse over the question marks on the surf forecast table itself. Please always bear in mind that the forecast is for near-shore open water and local factors at each surf break influence the actual breaking wave height, such as the beach / reef profile, water depths offshore and shelter.
Keta Reef Oshima is 1 km (1 miles) from the city of Oshima. If you plan a holiday in Izu Islands, look for hotels and other accommodation in Oshima. Oshima has rooms for a wide range of budgets as well as car hire and transport links.
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