Surf Forecasts:
Mainside surf forecast from 17 Jul 2026:
- Most powerful swell: Sunday 19 Jul, 12AM (local time) - 2.5ft (0.7m), 9s period, W swell with 76 kJ wave energy.
Best Forecast Surf Conditions for Mainside this week:
The most powerful waves expected at Mainside in the next 16 days are 0.7m 9s and forecast to arrive on Sunday (Jul 19) at 12AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.9m 8s period and expected on Monday (Jul 20) at 12AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 12AM (Sun 19th Jul) | 2.5ft (0.7m) 9s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Hey folks, Rusty here. Let's be straight with you: if you're looking to paddle out at Mainside over the next couple of weeks, it's going to be a tough stretch. The entire 16-day run is a long, flat, and mostly blown-out wait. There's honestly nothing good on offer until the very end, and even that comes with major caveats.
From now, Saturday the 18th of July, right through to Tuesday the 28th of July, it's a write-off. We're seeing tiny swell—mostly below 2 ft—from the west and east, with short, weak periods (7-10 seconds). The combined wave energy is pathetic, staying below 100 (71, 55, 64...) which is a total energy drought. Winds are mostly cross or cross-onshore, adding chop to an already flat line-up. The water temp is about average for the time of year. You'd be wasting your time.
Then, around Wednesday the 29th of July, things get interesting, but not for surfing. A big pulse of energy arrives from the east with a 12-second period, and combined energy jumps to 714—moderate to strong. But the swell is 5 ft, and a storm force WSW wind (62 mph) is smashing it. This is a total mess. By the 30th, the swell hits 5 ft with a 13-second period, and combined energy is 957 to 1162, but severe gales and storm force cross-onshore winds have it completely blown out. This is kite-surfing territory, not paddle-surfing.
Finally, on Friday the 31st of July and into Saturday the 1st of August, the swell goes huge: 12 ft to 20 ft. The combined energy skyrockets into the thousands (1997, 3168, 14181, 15665). But here's the problem—it's a short-period, 8-second wind swell from the NW and W, with onshore gales (37-44 mph). It's raw, dangerous, and massive. The only standout possible window is Saturday afternoon the 1st of August. The forecast shows a 15 ft swell from the north with a very long 13-second period and strong breeze onshore wind. The data notes that while wind and tide might be favorable, the swell is predicted to be too big for this break. For experts only, if you have the skills and a death wish. Otherwise, save your energy.
So, it's a long, flat, stormy gap until the very last day or two, and that's a serious, expert-only (or kite-only) proposition. Forecasts change, so keep an eye on it, but right now, Mainside is a no-go.
- Rusty
Short Range ForecastMostly dry. Warm (max 30°C on Sun afternoon, min 27°C on Fri night). Wind will be generally light. | Days 5-7 Weather SummaryMostly dry. Warm (max 29°C on Tue morning, min 27°C on Tue night). Wind will be generally light. | ||||||||||||||||||
Saturday 18 | Sunday 19 | Monday 20 | Tuesday 21 | Wednesday 22 | Thursday 23 | ||||||||||||||
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) | W 7 | W 8 | W 8 | W 9 | W 8 | W 7 | W 7 | W 8 | W 7 | W 7 | W 7 | ENE 9 | ENE 9 | E 9 | E 9 | ENE 11 | ENE 10 | ENE 10 | ENE 10 |
Wave Graph  | |||||||||||||||||||
 kJ | 34 | 71 | 55 | 76 | 57 | 37 | 22 | 42 | 23 | 22 | 15 | 16 | 16 | 15 | 15 | 23 | 20 | 20 | 19 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | cross | cross | cross | cross-off | cross | cross-on | cross | cross-on | cross-on | glassy | glassy | glassy | cross-off | glassy | cross | cross-off |
High Tide | 9:49PM2.07m | 9:32AM2.11m | 10:23PM2.04m | 10:17AM1.97m | 10:58PM1.99m | 11:06AM1.81m | 11:36PM1.93m | 12:03PM1.64m | 00:16AM1.86m | 1:20PM1.50m | 1:05AM1.79m | 3:13PM1.44m | 2:07AM1.74m | ||||||
Low Tide | 3:41AM0.75m | 4:02PM0.33m | 4:25AM0.73m | 4:39PM0.51m | 5:13AM0.73m | 5:16PM0.71m | 6:06AM0.76m | 5:55PM0.91m | 7:09AM0.79m | 6:40PM1.09m | 8:26AM0.79m | 7:46PM1.24m | |||||||
 |  | | | |  |  | | | | | | | | | | | | | |
 | — | 5:46 | — | — | 5:47 | — | — | 5:47 | — | — | 5:48 | — | — | 5:48 | — | — | 5:48 | — | — |
 | 7:22 | — | 7:22 | — | — | 7:22 | — | — | 7:22 | — | — | 7:22 | — | — | 7:22 | — | — | 7:21 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 28 | 28 | 29 | 28 | 28 | 30 | 29 | 29 | 28 | 28 | 29 | 28 | 28 | 28 | 29 | 28 | 28 | 29 | 28 |
Feels °C | 32 | 33 | 33 | 33 | 33 | 34 | 32 | 32 | 31 | 33 | 33 | 31 | 33 | 33 | 34 | 33 | 32 | 33 | 33 |
Swell 1 Height (m) Direction Period (s) | W 7 | W 8 | W 8 | W 9 | W 8 | W 7 | SW 8 | W 8 | W 7 | SW 7 | SW 7 | SW 7 | SW 7 | SW 7 | WSW 6 | SW 7 | SW 7 | SW 7 | ENE 10 |
| kJ | 34 | 71 | 55 | 76 | 57 | 37 | 45 | 42 | 23 | 44 | 32 | 24 | 25 | 16 | 17 | 14 | 8 | 9 | 19 |
Swell 2 Height (m) Direction Period (s) | ESE 9 | SW 8 | SW 8 | SW 8 | SW 8 | SW 8 | W 7 | E 10 | E 10 | W 7 | W 7 | W 6 | ENE 9 | E 9 | E 9 | ENE 11 | W 6 | ENE 10 | SW 8 |
| kJ | 8 | 55 | 40 | 51 | 46 | 49 | 22 | 7 | 7 | 22 | 15 | 7 | 16 | 15 | 15 | 23 | 7 | 20 | 9 |
Swell 3 Height (m) Direction Period (s) | E 10 | SE 9 | SE 8 | E 10 | E 10 | E 10 | E 9 | SE 9 | SE 9 | ENE 10 | ENE 9 | ENE 9 | W 6 | W 6 | NE 13 | W 8 | ENE 10 | W 6 | W 6 |
| kJ | 8 | 3 | 3 | 7 | 7 | 7 | 7 | 3 | 3 | 9 | 8 | 16 | 3 | 7 | 6 | 10 | 20 | 6 | 2 |
Wind waves Height (m) Direction Period (s) | SW 8 | — | — | — | — | — | SW 8 | SW 7 | SW 7 | — | — | — | — | — | — | — | — | — | — |
| kJ | 43 | — | — | — | — | — | 82 | 44 | 54 | — | — | — | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 652 | 36 | 59 | 6 | 6 | 59 | 608 | 59 | 74 | 36 | 36 | 36 | 36 | 36 | 36 | 25 | 25 | 41 | 25 |
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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