Surf Forecasts:
Mainside surf forecast from 23 Aug 2026:
- Best quality surf: Friday 28 Aug, 12PM (local time) - 3ft (0.9m), 9s period, E swell with offshore winds.
- Most powerful swell: Tuesday 25 Aug, 9AM (local time) - 10ft (3.0m), 17s period, E swell with 5,088 kJ wave energy.
- Next surfable swell (1★+): Friday 28 Aug, 12PM (local time) - 3ft (0.9m), 9s period with E swell.
Best Forecast Surf Conditions for Mainside this week:
The surf forecast for Mainside over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Friday (Aug 28) at 12PM. The primary swell is predicted to be 0.9m and 9s period with a secondary swell of 0.2m and 15s. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Mainside in the next 16 days are 3.0m 17s and forecast to arrive on Tuesday (Aug 25) at 9AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 5.0m 9s period and expected on Wednesday (Aug 26) at 9PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 12PM (Fri 28th Aug) | 3ft (0.9m) 9s |
| Best Surf | 12PM (Fri 28th Aug) | 3ft (0.9m) 9s |
| Most Powerful | 9AM (Tue 25th Aug) | 10ft (3.0m) 17s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Hey, Rusty here again.
We’ve got a lean patch at Mainside. Most of the next couple weeks is a bust. A couple moments might get you out of the water, but don’t hold your breath.
Starting Sunday the 23rd, it’s tiny – 1 foot east swell, weak, short period. Clean but no power. Monday the 24th is flat.
Tuesday the 25th morning jumps to 10 feet east swell with a long 17-second period and strong energy (5088). That’s a serious groundswell for the reef. But wind is 25 km/h cross-shore and conditions are marginal. Too big for beginners, experts only. By afternoon it’s 40 km/h cross-onshore and messy. Not worth.
Wednesday the 26th is gale-force and blown out. Thursday the 27th clean but just 0.6 to 2 feet. Friday the 28th afternoon shows 3 feet east at 9 seconds (147 energy), clean – still weak. Saturday the 29th back to 0.6 feet.
Sunday the 30th morning offers 3 feet east, short 7-second period (92 energy), offshore wind – surfable but ordinary.
The standout is Tuesday the 1st of September: 7 to 8 feet east-northeast swell, short period, clean cross-offshore wind, moderate energy (770-806). This is your best window. For experienced surfers only. Crowds are sometimes an issue, so expect some.
From Wednesday the 2nd through Monday the 7th, it’s all nasty – gale winds, tiny surf, blown out. The 7th morning has 6 feet from the north-west (535 energy) but it’s cross-onshore and marginal.
Overall, this 16-day stretch is rough. The real standout is Tuesday the 1st of September morning with clean 7 to 8 foot waves. The rest is mostly flat or messy.
Rusty.
Short Range ForecastLight rain (total 7mm), mostly falling on Tue night. Warm (max 29°C on Mon afternoon, min 27°C on Sun night). Winds increasing (light winds from the E on Sun night, gales from the WNW by Tue night). | Days 4-6 Weather SummaryModerate rain (total 15mm), heaviest on Wed night. Warm (max 29°C on Fri morning, min 27°C on Wed afternoon). Winds decreasing (gales from the W on Wed morning, moderate winds from the SE by Fri night). | ||||||||||||||||||||
Sunday 23 | Monday 24 | Tuesday 25 | Wednesday 26 | Thursday 27 | Friday 28 | Saturday 29 | |||||||||||||||
AM | PM | 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) | E 14 | E 9 | E 8 | ESE 16 | ENE 10 | ENE 7 | E 17 | E 16 | E 15 | NNE 12 | NNW 11 | WNW 10 | E 13 | E 8 | E 9 | E 15 | E 9 | E 9 | ENE 13 | ENE 13 | ENE 12 |
Wave Graph  | |||||||||||||||||||||
 kJ | 37 | 6 | 5 | 0 | 11 | 57 | 5088 | 4117 | 3430 | 3293 | 4832 | 1908 | 13 | 46 | 108 | 17 | 130 | 171 | 17 | 17 | 15 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | off | off | off | off | cross-off | cross | cross-on | cross-on | cross-on | cross-on | cross-off | cross-off | cross-off | off | off | cross-off | off | off | off | off |
High Tide | 6:02PM1.61m | 4:01AM1.63m | 6:26PM1.73m | 5:05AM1.73m | 6:47PM1.83m | 5:50AM1.85m | 7:07PM1.92m | 6:28AM1.97m | 7:28PM2.00m | 7:03AM2.08m | 7:50PM2.07m | 7:38AM2.16m | 8:14PM2.11m | ||||||||
Low Tide | 10:25AM0.77m | 11:03PM1.37m | 11:21AM0.66m | 11:53PM1.25m | 12:00PM0.54m | 00:24AM1.12m | 12:33PM0.45m | 00:51AM0.99m | 1:03PM0.38m | 1:16AM0.84m | 1:32PM0.34m | 1:43AM0.70m | 2:01PM0.34m | 2:13AM0.58m | |||||||
 | |  | | | | |  |  | |  |  | | | |  | | | | | | |
 | 6:03 | — | — | 6:03 | — | — | 6:05 | — | — | 6:05 | — | — | 6:05 | — | — | 6:05 | — | — | 6:07 | — | — |
 | — | 6:59 | — | — | 6:58 | — | — | 6:57 | — | — | 6:55 | — | — | 6:54 | — | — | 6:53 | — | — | 6:52 | — |
mm | — | — | — | — | — | — | — | — | 7 | — | 2 | 6 | 2 | 3 | 1 | 1 | — | — | — | 1 | — |
Temp °C | 28 | 28 | 27 | 28 | 29 | 27 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 29 | 29 | 28 | 29 | 29 | 28 |
Feels °C | 30 | 29 | 28 | 31 | 31 | 29 | 29 | 27 | 24 | 20 | 23 | 24 | 25 | 26 | 28 | 31 | 30 | 30 | 31 | 30 | 31 |
Swell 1 Height (m) Direction Period (s) | SSW 10 | SSW 10 | SW 9 | SW 9 | ESE 15 | ESE 18 | E 17 | E 16 | E 15 | NNE 12 | NNW 11 | WNW 10 | WSW 10 | E 8 | SW 12 | SW 11 | SW 10 | SW 11 | SW 11 | SW 10 | SW 10 |
| kJ | 457 | 363 | 188 | 93 | 539 | 2552 | 5088 | 4117 | 3430 | 3293 | 4832 | 1908 | 1905 | 46 | 2196 | 935 | 659 | 664 | 572 | 266 | 136 |
Swell 2 Height (m) Direction Period (s) | E 14 | ESE 13 | ESE 12 | ESE 16 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | E 11 | E 11 | E 13 | E 13 | E 16 | E 15 | E 9 | E 9 | ENE 13 | S 10 | S 9 |
| kJ | 37 | 17 | 30 | 220 | 79 | 79 | 64 | 37 | 37 | 39 | 39 | 20 | 13 | 13 | 5 | 17 | 130 | 171 | 17 | 138 | 83 |
Swell 3 Height (m) Direction Period (s) | SE 10 | E 9 | E 8 | SE 9 | ENE 10 | ENE 10 | — | — | — | SSW 9 | SE 10 | E 13 | — | E 18 | SE 15 | SE 10 | E 15 | — | — | ENE 13 | ENE 12 |
| kJ | 4 | 6 | 5 | 3 | 11 | 19 | — | — | — | 53 | 4 | 14 | — | 6 | 8 | 4 | 17 | — | — | 17 | 15 |
Wind waves Height (m) Direction Period (s) | SSE 7 | SSE 4 | ESE 4 | E 4 | E 6 | ENE 7 | — | NNE 5 | N 7 | NW 8 | W 9 | SSW 9 | SSE 8 | SSW 11 | E 9 | ESE 8 | — | SE 4 | ESE 8 | ESE 8 | ESE 7 |
| kJ | 78 | 24 | 13 | 12 | 38 | 57 | — | 93 | 495 | 1323 | 2454 | 3775 | 1072 | 2664 | 108 | 120 | — | 22 | 183 | 123 | 132 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 14 | 14 | 14 | 14 | 14 | 10 | 39 | 608 | 608 | 735 | 608 | 622 | 736 | 735 | 735 | 14 | 608 | 0 | 14 | 14 | 14 |
Best forecast wave conditions in Okinawa | |||||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||||
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Information about the Mainside Surf forecast
The above surf forecast table for Mainside provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Mainside can be found by selecting the local surf guide option on the grey menu. Our Mainside 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 (Mainside) 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 Mainside 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.
Mainside is 11 km (7 miles) from the city of Ishikawa. If you plan a holiday in Okinawa, look for hotels and other accommodation in Ishikawa. Ishikawa has rooms for a wide range of budgets as well as car hire and transport links.
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