Rock Island Surf Break

Lat Long: 35.29° N 139.55° E

Rock Island Surf Forecast and Surf Report

Issued: 8 am 01 Aug 2026 (local time)

Forecast update in  hr  min

Today's Rock Island sea temperature is
27.6° C
1.1° 

Rock Island surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.


Rock Island surf forecast from 1 Aug 2026:

  • Best quality surf: Wednesday 5 Aug, 3PM (local time) - 10ft (3.0m), 16s period, SSE swell with offshore winds.
  • Most powerful swell: Wednesday 5 Aug, 6PM (local time) - 10ft (3.0m), 16s period, SSE swell with 4,483 kJ wave energy.
  • Next surfable swell (1★+): Sunday 2 Aug, 12AM (local time) - 1ft (0.3m), 17s period with SE swell.

Best Forecast Surf Conditions for Rock Island this week:

The surf forecast for Rock Island over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Sunday (Aug 02) at 12AM. The primary swell is predicted to be 0.3m and 17s period with a secondary swell of 0.4m and 6s. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Rock Island in the next 16 days are 3.0m 16s and forecast to arrive on Wednesday (Aug 05) at 6PM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.6m 3s period and expected on Tuesday (Aug 04) at 12AM.

Wave TypeTime (JST) & Date Wave Height & Period
Next good surf (1 star+)12AM (Sun 2nd Aug)1ft (0.3m) 17s
Best Surf 3PM (Wed 5th Aug)10ft (3.0m) 16s
Most Powerful 6PM (Wed 5th Aug)10ft (3.0m) 16s

Table - best surf conditions forecast for Rock Island over the next 16 days.


The Lowdown

Right folks, Rusty here. We’ve got a bit of a slow starter on our hands at Rock Island, but once it kicks in, it’s going to be a solid few days for the experienced crew. The water’s sitting at a warm 82°, which is a touch warmer than normal for this time of year, so you might not need the thickest rubber.

The first few days are a write-off. Saturday morning and afternoon are flat with poor conditions, so leave the board in the car. Sunday the 2nd has some tiny, tiny waves, barely surfable, but the wind is cross-off and the wave energy is weak (112). You could get wet, but it’s hardly worth it. Come Monday the 3rd, the swell starts to build, but the conditions are still marginal. The energy is picking up, hitting 303 on Monday morning and 488 in the afternoon, but the wind is a moderate offshore at 15 mph, which cleans things up a bit. The swell is still under 3 ft though, so it’s a bit of a tease.

Now, Tuesday the 4th is where it starts to get interesting. The morning is clean with a fresh NNE offshore at 19 mph. The swell is 5 ft from the SE, with a very long period of 17 seconds. The energy is ramping up big time (1271). This is proper groundswell energy, but at this size, it’s getting into the intermediate zone. The afternoon sees it hit 6 ft.

Wednesday the 5th is the absolute standout. The morning has an 8 ft SSE swell with a 16-second period – that’s serious groundswell. The energy is enormous (3834), and the wind is a moderate offshore from the NNE at 16 mph. The conditions are excellent for experienced surfers. This is big, powerful, and clean. The afternoon is even bigger at 10 ft from the SSE, with energy hitting 4320 and lighter cross-off winds. This is expert-only territory. Thursday the 6th morning holds the size at 8 ft from the S, still clean with light cross-off winds and energy at 3588. This is another day for the advanced crew. Thursday afternoon though, the wind swings onshore, making it messy.

Friday the 7th morning is a glassy beauty with a 6 ft SSW swell and a 14-second period. The energy is still strong (1550), and with glassy conditions, the waves will be clean. It’s still a solid size for experienced surfers. The afternoon turns onshore and becomes a mess.

After that, it drops off. Saturday the 8th and Sunday the 9th have smaller, onshore swell, and the following week is a long stretch of tiny, weak waves with no real quality until the 16th of August. That Sunday the 16th morning sees a 6 ft SE swell return with a moderate offshore wind and energy at 1208, which looks promising. The afternoon has 5 ft with a clean offshore wind and a score for very good surf. That’s a solid option for the end of the outlook.

So, to call it: Wednesday the 5th and Thursday morning the 6th are the top of the heap. Big, powerful, clean groundswell for the experts. The 7th morning is a close second with glassy conditions. The mid-period stuff is a no-go, and the end of the outlook on the 16th is a promising but less certain bet.

Rusty.

Short Range Forecast

Light rain (total 2mm), mostly falling on Sat night. Warm (max 31°C on Sun morning, min 23°C on Sun night). Winds increasing (calm on Sat morning, fresh winds from the NE by Mon night).

Days 4-6 Weather Summary

Light rain (total 6mm), mostly falling on Thu night. Warm (max 30°C on Thu morning, min 23°C on Tue night). Mainly fresh winds.

Saturday
1
Sunday
2
Monday
3
Tuesday
4
Wednesday
5
Thursday
6
Friday
7
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
0
1
0
1
0
1
2
2
3
2
3
4
5
5
5
4
3
3
2
4
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.3
SSW
7
0.4
SSW
6
0.3
SE
17
0.4
ESE
16
0.5
SE
15
0.6
ESE
15
0.7
SE
16
0.9
ESE
16
1.1
SE
17
1.4
SE
17
1.7
SE
17
2.2
SE
16
2.5
SSE
16
3
SSE
16
3
SSE
16
3
S
16
3
S
16
2.5
S
16
2.4
S
16
2.3
S
16
2
S
15
Wave Graph
Metric surfscale
Energy kJ
9
14
46
99
104
148
261
452
633
1133
1575
2527
3444
4006
4288
4401
3955
2987
2789
2601
1787
Wind (km/h)
0
SSE
10
SSW
0
ESE
15
NE
15
E
25
NE
30
NNE
25
NNE
30
NNE
30
NNE
25
NE
30
NNE
30
NNE
20
NNE
25
NNE
25
NNE
10
ESE
15
ENE
15
ENE
20
SE
15
ENE
Wind State
glassy
on
glassy
cross-off
cross-off
off
off
off
off
off
cross-off
off
off
off
off
off
cross
cross-off
cross-off
cross
cross-off
High Tide
7:32PM1.46m
6:50AM1.50m
7:56PM1.45m
7:38AM1.44m
8:21PM1.45m
8:29AM1.35m
8:48PM1.44m
9:29AM1.26m
9:16PM1.43m
10:48AM1.17m
9:49PM1.41m
12:41PM1.13m
10:30PM1.40m
Low Tide
12:51PM0.19m
1:07AM0.73m
1:26PM0.30m
1:46AM0.65m
1:59PM0.44m
2:29AM0.59m
2:32PM0.59m
3:17AM0.54m
3:04PM0.75m
4:14AM0.50m
3:39PM0.90m
5:21AM0.46m
4:23PM1.04m
clear
part cloud
rain showers
clear
part cloud
cloud
cloud
part cloud
clear
clear
part cloud
cloud
part cloud
part cloud
clear
part cloud
clear
thunderstorm
rain showers
clear
thunderstorm
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
4:48
4:50
4:50
4:52
4:52
4:52
4:54
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:45
6:45
6:44
6:43
6:42
6:40
6:39
 mm
2
6
1
5
Temp °C
29
30
28
31
31
25
24
26
24
26
27
24
25
28
26
30
30
27
30
30
26
Feels °C
33
33
33
33
33
24
22
24
21
23
24
22
23
28
26
31
32
29
32
30
28
  • Map Icons:
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  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
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Information about the Rock Island Surf forecast

The above surf forecast table for Rock Island provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Rock Island can be found by selecting the local surf guide option on the grey menu. Our Rock Island 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 (Rock Island) 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 Rock Island 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.

Rock Island is 3 km (2 miles) from the city of Kamakura. If you plan a holiday in Kanagawa, look for hotels and other accommodation in Kamakura. Kamakura has rooms for a wide range of budgets as well as car hire and transport links.

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