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Surf Forecasts:
Rock Island surfForecast / Kanagawa / Japan
48hr Weather and Surf, issued 8 pm Wednesday 22 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
18.7° 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 3AM is: 0.4m 6s primary swell from a South-southeast direction and 0.3m 8s secondary swell from a Southeast direction (forecast issued at 08:00pm April 22). The wind direction is predicted to be cross-offshore.
| Time (JST) & Date | Wave Height | Wave Period |
|---|---|---|
| Morning (23 Apr) | 1.5ft (0.4m) | 6s |
| 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 38mm), heaviest during Thu night. Very mild (max 19°C on Wed night, min 12°C on Thu night). Winds decreasing (strong winds from the NNE on Thu night, calm by Sat morning). | ||||||||||||||||||||||||
Wed 22 | Thursday 23 | Friday 24 | Saturday 25 | |||||||||||||||||||||
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 | 12 PM | 3 PM | |
Swell Height Map |   |    |    |    | ||||||||||||||||||||
S 4 | S 5 | S 5 | SSE 6 | SSE 6 | SSE 6 | SE 6 | SE 6 | E 9 | E 9 | E 9 | E 9 | S 8 | S 8 | S 8 | SSE 9 | S 8 | S 8 | S 8 | S 8 | S 8 | S 7 | SE 7 | SSE 7 | |
30 | 21 | 15 | 12 | 14 | 16 | 10 | 10 | 8 | 7 | 7 | 7 | 10 | 30 | 35 | 27 | 34 | 34 | 33 | 18 | 18 | 17 | 11 | 16 | |
Wind (km/h) | ||||||||||||||||||||||||
on | on | on | cross-off | off | off | cross-off | cross-off | off | off | off | off | off | off | cross-off | cross | cross-on | cross | cross-off | cross-off | cross-off | cross-off | glassy | on | |
High Tide | 9:35PM1.19m | 7:17AM1.30m | 10:46PM1.15m | 7:59AM1.22m | 00:06AM1.14m | 9:04AM1.13m | ||||||||||||||||||
Low Tide | 2:05AM0.95m | 2:59PM0.11m | 3:02AM1.00m | 3:59PM0.20m | 4:39AM1.00m | |||||||||||||||||||
 |  |  | | | |  | |  |  | |  | |  | | | |  | | | |  | | | |
 | — | — | — | 5:00 | — | — | — | — | — | — | — | 4:58 | — | — | — | — | — | — | — | 4:58 | — | — | — | — |
 | 6:19 | — | — | — | — | — | — | — | 6:20 | — | — | — | — | — | — | — | 6:21 | — | — | — | — | — | — | 6:21 |
— | — | — | — | — | — | 1 | 4 | 6 | 12 | 11 | 3 | 1 | — | — | — | — | — | — | — | — | — | — | — | |
Temp °C | 18 | 19 | 18 | 18 | 18 | 18 | 16 | 14 | 13 | 12 | 13 | 13 | 12 | 13 | 16 | 17 | 16 | 15 | 14 | 14 | 14 | 13 | 15 | 16 |
13 | 16 | 17 | 17 | 14 | 16 | 14 | 11 | 7 | 3 | 5 | 6 | 6 | 8 | 11 | 14 | 12 | 12 | 11 | 10 | 9 | 9 | 13 | 12 | |
Swell 1 Height (m) Direction Period (s) | SE 8 | SE 8 | S 5 | SSE 6 | SSE 6 | SSE 6 | SE 6 | SE 6 | SSE 6 | SSE 6 | SE 6 | SE 6 | S 8 | S 8 | S 8 | SSE 9 | S 8 | S 8 | S 8 | S 8 | S 8 | S 7 | SE 7 | E 11 |
 kJ | 2 | 2 | 15 | 12 | 14 | 16 | 10 | 10 | 8 | 4 | 1 | 1 | 10 | 30 | 35 | 27 | 34 | 34 | 33 | 18 | 18 | 17 | 11 | 2 |
Swell 2 Height (m) Direction Period (s) | SE 13 | SE 13 | SE 8 | SE 8 | SE 7 | SE 12 | SE 12 | SE 12 | SE 12 | SE 12 | SE 12 | SE 12 | ESE 6 | SE 6 | SE 7 | SSW 8 | SE 12 | SE 12 | ESE 3 | SE 12 | SE 12 | SE 12 | SSW 8 | E 9 |
| kJ | 7 | 7 | 9 | 9 | 9 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 4 | 2 | 2 | 26 | 6 | 5 | 1 | 6 | 5 | 5 | 6 | 1 |
Swell 3 Height (m) Direction Period (s) | E 10 | E 10 | SE 13 | SE 13 | SE 13 | E 10 | E 9 | E 9 | E 9 | E 9 | E 9 | E 9 | SE 12 | SE 12 | SE 12 | SE 6 | SW 11 | SW 8 | SE 12 | — | — | E 9 | E 11 | SE 11 |
| kJ | 2 | 2 | 7 | 7 | 6 | 2 | 7 | 7 | 7 | 7 | 7 | 7 | 6 | 5 | 5 | 1 | 5 | 11 | 5 | — | — | 6 | 3 | 5 |
Wind waves Height (m) Direction Period (s) | S 4 | S 5 | — | — | — | — | — | — | NE 3 | NNE 3 | NNE 4 | NNE 4 | NNE 4 | NE 3 | NE 3 | ENE 3 | SE 2 | SE 3 | — | — | E 2 | ESE 3 | — | SSE 7 |
| kJ | 30 | 21 | — | — | — | — | — | — | 2 | 13 | 25 | 18 | 12 | 6 | 2 | 1 | 2 | 2 | — | — | 1 | 2 | — | 16 |
Nearest Offshore or Glassy | ||||||||||||||||||||||||
Distance (km) | 77 | 38 | 38 | 16 | 16 | 54 | 16 | 51 | 51 | 552 | 228 | 136 | 136 | 136 | 38 | 64 | 38 | 38 | 38 | 38 | 470 | 470 | 16 | 77 |
Best forecast wave conditions in Kanagawa | ||||||||||||||||||||||||
Best forecast wave conditions in Japan | ||||||||||||||||||||||||
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