Surf Forecasts:
Mainside surf forecast from 28 Jul 2026:
- Most powerful swell: Wednesday 5 Aug, 3AM (local time) - 5ft (1.6m), 17s period, E swell with 1,508 kJ wave energy.
Best Forecast Surf Conditions for Mainside this week:
The most powerful waves expected at Mainside in the next 16 days are 1.6m 17s and forecast to arrive on Wednesday (Aug 05) at 3AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.0m 16s period and expected on Monday (Aug 03) at 6PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 3AM (Wed 5th Aug) | 5ft (1.6m) 17s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Alright, Rusty here again. Let’s talk Mainside in imperial.
First few days are dead flat. From Wednesday July 29th through the start of August, you’re looking at barely a ripple. No swell to speak of – just a few inches of weak, short-period junk.
Tuesday August 4th is where it first hints at life. Morning brings 4ft swell from the east with a very long 18-second period – that's proper groundswell. Combined energy is 917 (moderate), with a cross-off breeze at 15 mph, clean conditions. It’s only marginal, but it’s a start. Afternoon nudges up to 4ft, energy 1060 (moderate), still clean.
Wednesday the 5th of August is the real standout. Morning delivers 5ft east swell, same long 18-second period, light cross-off wind, and energy of 1594 (strong). This is the peak of the whole forecast. Mainside is a consistent, exposed reef, so it’ll handle that long-period energy and shape up nicely. The wind is clean and the waves should have some power. This is your session, no question.
Then it falls apart. Thursday the 6th and Friday the 7th see onshore wind hitting 20-22 mph with swell up to 7ft – but it’s straight onshore, choppy, and ugly. Combined energy hits 2827 (very strong), but it’s completely blown out. Not a paddle surfer’s wave. Saturday the 8th drops to 5ft but with a cross-onshore chop, still poor.
Second week settles. Sunday the 9th is ordinary with 3ft waves. Monday the 10th gives you a small clean window – 2ft from the east at 16 seconds, offshore breeze, energy 257 (moderate). That is a glassy little longboard day. Tuesday the 11th is similar but weaker.
Wednesday the 12th brings 4ft east swell, period 8-9 seconds, offshore wind, energy 229 (moderate). Small but clean and rideable. Thursday the 13th pushes up to 5ft at 10 seconds, cross-off breeze, energy 495 (moderate). A solid finish to the run.
Best day by far is Wednesday August 5th. Second pick is Monday August 10th for cleaner but smaller surf.
Crowds at Mainside can pop up sometimes, so get out there early.
– Rusty
Short Range ForecastLight rain (total 6mm), mostly falling on Tue night. Warm (max 30°C on Wed afternoon, min 28°C on Tue night). Wind will be generally light. | Days 5-7 Weather SummaryMostly dry. Warm (max 30°C on Mon morning, min 28°C on Fri night). Wind will be generally light. | ||||||||||||||||||
Wednesday 29 | Thursday 30 | Friday 31 | Saturday 1 | Sunday 2 | Monday 3 | ||||||||||||||
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) | SE 10 | SE 10 | ESE 9 | ESE 9 | SW 8 | ESE 9 | E 13 | E 10 | E 9 | E 9 | E 9 | N 5 | N 5 | E 15 | E 17 | E 8 | N 4 | N 4 | E 16 |
Wave Graph  | |||||||||||||||||||
 kJ | 0 | 0 | 0 | 0 | 0 | 0 | 3 | 7 | 6 | 2 | 6 | 2 | 2 | 17 | 23 | 5 | 9 | 16 | 659 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | off | glassy | glassy | cross-off | glassy | glassy | cross-off | cross-on | cross-on | cross-off | cross-on | cross-on | cross-on | glassy | cross-on | cross-on | cross | cross | cross |
High Tide | 6:36AM1.94m | 8:02PM1.93m | 7:11AM2.02m | 8:25PM1.99m | 7:46AM2.08m | 8:49PM2.03m | 8:23AM2.11m | 9:15PM2.06m | 9:02AM2.11m | 9:44PM2.06m | 9:44AM2.05m | 10:15PM2.05m | |||||||
Low Tide | 1:09AM1.13m | 1:25PM0.32m | 1:37AM1.03m | 1:54PM0.28m | 2:05AM0.93m | 2:23PM0.27m | 2:35AM0.83m | 2:54PM0.31m | 3:08AM0.74m | 3:26PM0.39m | 3:45AM0.67m | 4:00PM0.51m | |||||||
 |  |  | | |  | | | |  | | | | | | | | |  | |
 | — | 5:52 | — | — | 5:52 | — | — | 5:52 | — | — | 5:52 | — | — | 5:54 | — | — | 5:54 | — | — |
 | 7:19 | — | 7:17 | — | — | 7:17 | — | — | 7:16 | — | — | 7:15 | — | — | 7:15 | — | — | 7:15 | — |
mm | 2 | — | 1 | 1 | 1 | — | 1 | — | — | — | — | — | — | — | — | — | — | — | 1 |
Temp °C | 29 | 29 | 30 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 30 | 30 | 29 |
Feels °C | 33 | 34 | 35 | 33 | 33 | 33 | 34 | 33 | 33 | 33 | 32 | 32 | 33 | 32 | 31 | 32 | 31 | 31 | 32 |
Swell 1 Height (m) Direction Period (s) | SE 10 | SE 10 | ESE 9 | ESE 9 | ESE 9 | ESE 9 | ESE 9 | SW 8 | SW 8 | SW 8 | SW 8 | SW 8 | SW 8 | E 15 | E 17 | E 16 | ESE 15 | ESE 16 | E 16 |
| kJ | 16 | 15 | 17 | 17 | 8 | 17 | 8 | 10 | 10 | 10 | 11 | 3 | 3 | 17 | 23 | 126 | 296 | 416 | 659 |
Swell 2 Height (m) Direction Period (s) | SW 8 | SW 8 | SW 8 | SW 8 | SW 8 | SW 8 | SW 8 | SE 9 | E 9 | E 9 | N 5 | N 5 | N 5 | SW 8 | E 14 | E 8 | SW 7 | SW 7 | SW 8 |
| kJ | 2 | 9 | 10 | 9 | 10 | 10 | 10 | 3 | 6 | 2 | 2 | 2 | 2 | 3 | 15 | 5 | 2 | 2 | 2 |
Swell 3 Height (m) Direction Period (s) | S 7 | ESE 5 | ESE 5 | SE 5 | SE 5 | S 7 | E 13 | E 10 | SE 10 | N 5 | E 9 | E 9 | SE 9 | SE 9 | SW 8 | SE 9 | — | S 7 | S 7 |
| kJ | 4 | 2 | 2 | 1 | 1 | 1 | 3 | 7 | 4 | 1 | 6 | 2 | 3 | 3 | 3 | 3 | — | 1 | 1 |
Wind waves Height (m) Direction Period (s) | ESE 4 | — | — | — | — | — | — | — | — | — | — | — | — | N 5 | N 5 | N 3 | N 4 | N 4 | N 4 |
| kJ | 2 | — | — | — | — | — | — | — | — | — | — | — | — | 2 | 2 | 2 | 9 | 16 | 18 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 10 | 36 | 36 | 660 | 699 | 995 | 73 | 760 | 796 | 1615 | 796 | 1010 | 652 | 36 | 24 | 24 | 27 | 622 | 9 |
Best forecast wave conditions in Okinawa | |||||||||||||||||||
Best forecast wave conditions in Japan | |||||||||||||||||||
Header Global | |||||||||||||||||||
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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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