Using Surf-Forecast’s Historical Surf Data To Find The Most Consistent Waves On Earth
Using our statistical data for 7000 spots dating back to 2006, we can find those waves that break the most, with the best winds.
Surf Forecasts:
Rock Island surfForecast / Kanagawa / Japan
48hr Weather and Surf, issued 8 pm Sunday 28 Dec 2025 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
17.1° C
(Which is 1.2°C colder than average for this time of year)How big are the waves at Rock Island today?
The current surf forecast for Rock Island at 4AM is: 0.1m 13s primary swell from a East direction and 0.1m 8s secondary swell from a Southeast direction (forecast issued at 08:00pm December 28). The wind direction is predicted to be offshore.
| Time (JST) & Date | Wave Height | Wave Period |
|---|---|---|
| Morning (29 Dec) | 0.5ft (0.1m) | 13s |
| Afternoon (29 Dec) | 0.5ft (0.1m) | 12s |
| Evening (29 Dec) | 2.5ft (0.7m) | 5s |
Table - waves today at Rock Island. (Swell directed towards the surf break)
Updates in hr min s Forecast update imminent
Sun 28 | Monday 29 | Tuesday 30 | Wednesday 31 | |||||||||||||||||||||
| 6 PM | 9 PM | 0 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | 6 PM | 9 PM | 0 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | 6 PM | 9 PM | 0 AM | 3 AM | 6 AM | 9 AM | 12 PM | 3 PM | |
Rating (10 max) | ||||||||||||||||||||||||
Swell Height Map |   |    |    |    | ||||||||||||||||||||
| Wave Height (m) & direction (?) | ||||||||||||||||||||||||
| Period(s) (?) | 8 | 8 | 13 | 13 | 13 | 13 | 13 | 12 | 4 | 5 | 5 | 5 | 5 | 5 | 5 | 5 | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 5 |
Wave (?)Graph  | ||||||||||||||||||||||||
 kJ (?) | 2 | 2 | 4 | 3 | 3 | 3 | 3 | 3 | 7 | 25 | 87 | 94 | 67 | 49 | 52 | 20 | 72 | 139 | 72 | 102 | 112 | 22 | 12 | 5 |
Wind (km/h) | ||||||||||||||||||||||||
| Wind State (?) onshore cross-onshore cross-shore cross-offshore offshore glassy | cross- off | cross- off | off | off | off | off | glass | on | cross- on | cross- on | cross | cross | cross- off | glass | cross- on | cross | cross- off | cross | cross- off | cross- off | off | off | glass | cross- off |
High Tide / height (m) | 11:45PM 1.07 | 11:42AM 1.30 | 1:29AM 1.08 | 12:23PM 1.32 | 3:01AM 1.14 | 1:07PM 1.34 | ||||||||||||||||||
Low Tide / height (m) | 5:44PM 0.60 | 5:15AM 0.71 | 6:49PM 0.48 | 6:18AM 0.85 | 7:50PM 0.34 | 7:29AM 0.95 | ||||||||||||||||||
Sun 28 | Monday 29 | Tuesday 30 | Wednesday 31 | |||||||||||||||||||||
| Sunrise | - | - | - | - | - | 6:48 | - | - | - | - | - | - | - | 6:48 | - | - | - | - | - | - | - | 6:50 | - | - |
| Sunset | - | - | - | - | - | - | - | 4:37 | - | - | - | - | - | - | - | 4:37 | - | - | - | - | - | - | - | 4:37 |
 |  |  | |  |  | | | | | | | |  |  | | | | | | | | | | |
Rain (mm) | - | - | - | - | 1 | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - | - |
| Temp. °C | 10 | 10 | 9 | 9 | 8 | 8 | 9 | 12 | 13 | 12 | 10 | 9 | 9 | 9 | 11 | 13 | 12 | 12 | 11 | 10 | 9 | 9 | 10 | 11 |
| Feels °C (?) | 6 | 6 | 6 | 5 | 3 | 4 | 7 | 8 | 6 | 6 | 5 | 5 | 6 | 7 | 8 | 9 | 8 | 9 | 6 | 7 | 4 | 5 | 7 | 7 |
- Map Icons:
Break
Live Wave Height (m)
Live Wind Speed (km/h)
Surf Rating (10 Max)
Ocean Swells (m)- Wind Speed (km/h)
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