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Surf Forecasts:
Rock Island surfForecast / Kanagawa / Japan
48hr Weather and Surf, issued 2 pm Thursday 23 Apr 2026 JSTForecast update in hr min s Forecast update imminent
Rock Island surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.
Today's Rock Island sea temperature is
18.6° C
(Which is normal for this time of year)How big are the waves at Rock Island today?
The current surf forecast for Rock Island at 6PM is: 0.4m 6s primary swell from a Southeast direction and 0.1m 12s secondary swell from a Southeast direction (forecast issued at 02:00pm April 23). The wind direction is predicted to be cross-shore.
| Time (JST) & Date | Wave Height | Wave Period |
|---|---|---|
| Morning (23 Apr) | - | - |
| Afternoon (23 Apr) | 1.5ft (0.4m) | 6s |
| Evening (23 Apr) | 0.5ft (0.2m) | 9s |
Table - waves today at Rock Island. (Swell directed towards the surf break)
Updates in hr min s Forecast update imminent
Short Range ForecastHeavy rain (total 32mm), heaviest during Thu night. Very mild (max 18°C on Fri afternoon, min 13°C on Fri night). Winds decreasing (fresh winds from the NNE on Thu night, calm by Sun morning). | ||||||||||||||||||||||||
Thu 23 | Friday 24 | Saturday 25 | Sun 26 | |||||||||||||||||||||
12 PM | 3 PM | 6 PM | 9 PM | 12 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | 6 PM | 9 PM | 12 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | 6 PM | 9 PM | 12 AM | 3 AM | 6 AM | 9 AM | |
Swell Height Map |    |    |    |    | ||||||||||||||||||||
SE 6 | SE 6 | SE 6 | E 9 | E 9 | SE 6 | SSW 9 | SSW 8 | S 8 | S 9 | S 8 | S 8 | S 8 | S 8 | S 8 | S 8 | SSE 7 | SSE 7 | SE 5 | SE 5 | SE 5 | SE 6 | SE 6 | SE 6 | |
11 | 11 | 10 | 7 | 7 | 9 | 7 | 37 | 39 | 38 | 50 | 49 | 33 | 31 | 29 | 18 | 21 | 17 | 7 | 7 | 5 | 8 | 8 | 9 | |
Wind (km/h) | ||||||||||||||||||||||||
glassy | cross-off | cross | off | off | off | off | off | cross-off | cross-off | cross | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | cross | cross | cross-off | cross-off | cross-off | cross-off | |
High Tide | 10:46PM1.15m | 7:59AM1.22m | 00:06AM1.14m | 9:04AM1.13m | 1:11AM1.16m | |||||||||||||||||||
Low Tide | 2:59PM0.11m | 3:02AM1.00m | 3:59PM0.20m | 4:39AM1.00m | 5:12PM0.29m | 6:36AM0.92m | ||||||||||||||||||
 |  |  |  |  |  | | | | | |  | | | |  | | | |  | | | | | |
 | — | — | — | — | — | 4:58 | — | — | — | — | — | — | — | 4:58 | — | — | — | — | — | — | — | 4:56 | — | — |
 | — | — | 6:20 | — | — | — | — | — | — | — | 6:21 | — | — | — | — | — | — | — | 6:21 | — | — | — | — | 6:22 |
— | 2 | 8 | 13 | 6 | 2 | 1 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | |
Temp °C | 18 | 15 | 14 | 14 | 14 | 14 | 14 | 15 | 17 | 18 | 16 | 15 | 14 | 13 | 13 | 13 | 15 | 16 | 15 | 14 | 14 | 14 | 14 | 15 |
18 | 14 | 13 | 10 | 8 | 8 | 9 | 10 | 12 | 14 | 12 | 11 | 9 | 7 | 8 | 8 | 11 | 12 | 10 | 10 | 11 | 12 | 12 | 13 | |
Swell 1 Height (m) Direction Period (s) | SE 6 | SE 6 | SE 6 | SSE 6 | SE 5 | SE 6 | SE 6 | SSW 8 | S 8 | S 9 | S 8 | S 8 | S 8 | S 8 | S 8 | S 8 | SSE 7 | SSE 7 | S 7 | S 7 | SE 5 | SE 6 | SE 6 | SE 6 |
 kJ | 11 | 11 | 10 | 4 | 4 | 9 | 6 | 37 | 31 | 38 | 50 | 49 | 33 | 31 | 29 | 18 | 21 | 17 | 4 | 4 | 5 | 8 | 8 | 9 |
Swell 2 Height (m) Direction Period (s) | SE 12 | SE 12 | SE 12 | SE 12 | SE 12 | SE 12 | SSW 9 | SSE 8 | SSW 8 | SSW 8 | SE 12 | SE 12 | SE 12 | — | E 12 | E 12 | SE 12 | E 11 | SW 8 | S 7 | S 7 | S 7 | S 7 | SE 8 |
| kJ | 6 | 6 | 6 | 6 | 6 | 6 | 7 | 27 | 39 | 26 | 5 | 5 | 5 | — | 3 | 3 | 5 | 2 | 2 | 1 | 1 | 1 | 1 | 3 |
Swell 3 Height (m) Direction Period (s) | — | E 9 | E 9 | E 9 | E 9 | E 9 | SE 12 | SE 12 | E 6 | SE 12 | E 8 | SE 12 | SE 12 | SE 12 | SE 12 | SW 8 | SE 11 | S 7 | E 11 | E 11 | S 6 | — | — | S 7 |
| kJ | — | 7 | 7 | 7 | 7 | 7 | 5 | 5 | 1 | 5 | 6 | 5 | 5 | 5 | 5 | 11 | 5 | 4 | 2 | 2 | 1 | — | — | 1 |
Wind waves Height (m) Direction Period (s) | — | — | — | — | NE 3 | NNE 4 | NNE 4 | NNE 3 | NE 3 | — | ESE 2 | ESE 2 | E 2 | ENE 2 | ENE 3 | E 3 | E 6 | ESE 2 | SE 5 | SE 5 | — | — | — | — |
| kJ | — | — | — | — | 5 | 11 | 8 | 4 | 1 | — | 1 | 1 | 1 | 1 | 3 | 1 | 22 | 1 | 7 | 7 | — | — | — | — |
Nearest Offshore or Glassy | ||||||||||||||||||||||||
Distance (km) | 51 | 51 | 77 | 86 | 228 | 136 | 38 | 8 | 12 | 64 | 38 | 38 | 38 | 145 | 488 | 145 | 2 | 64 | 794 | 77 | 38 | 38 | 145 | 77 |
Best forecast wave conditions in Kanagawa | ||||||||||||||||||||||||
Best forecast wave conditions in Japan | ||||||||||||||||||||||||
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