
Surf Forecasts:
Mainside surf forecast from 31 Jul 2026:
- Best quality surf: Thursday 6 Aug, 6AM (local time) - 13ft (4.0m), 20s period, E swell with cross-onshore winds.
- Most powerful swell: Thursday 6 Aug, 9PM (local time) - 23ft (7.0m), 14s period, N swell with 19,377 kJ wave energy.
- Next surfable swell (1★+): Thursday 6 Aug, 6AM (local time) - 13ft (4.0m), 20s 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 Thursday (Aug 06) at 6AM. The primary swell is predicted to be 4.0m and 20s period with a secondary swell of 3.5m and 8s. The wind is predicted to be cross-onshore as the swell arrives.
The most powerful waves expected at Mainside in the next 16 days are 7.0m 14s and forecast to arrive on Thursday (Aug 06) at 9PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 7.5m 11s period and expected on Friday (Aug 07) at 3AM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 6AM (Thu 6th Aug) | 13ft (4.0m) 20s |
| Best Surf | 6AM (Thu 6th Aug) | 13ft (4.0m) 20s |
| Most Powerful | 9PM (Thu 6th Aug) | 23ft (7.0m) 14s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
G’day, Rusty here. Look, I’m not gonna sugarcoat it – we’ve got a pretty quiet run ahead at Mainside for the next little while. For the first few days, it’s basically flat or close to it, with barely a bump worth paddling for. That stretch runs from Friday the 31st of July right through until Monday the 3rd of August. You’ll be looking at clean, glassy conditions on Friday morning with the water sitting at a warm 86.0°, about 1.8° warmer than usual for this time of year, but swell’s only 0.7 ft from the east at a short 10 seconds – total energy is just 7, basically nothing.
From Saturday the 1st through to Monday the 3rd, it stays tiny. The odd 0.7 ft east pulse shows up Sunday morning but the period jumps to 19 seconds, and energy’s only 48 – that’s a long period groundswell trying to push through but way too small to do anything at this exposed reef. Winds stay light and mostly onshore or cross-on through that stretch, so it’s not even clean.
Tuesday the 4th is where things start to change. By the morning, we’ve got 4.3 ft east swell with an 18-second period, and energy jumps right up to 1066 – moderate wave energy. The wind’s a cross-shore breeze from the north at 12 mph, so not perfect but it’s surfable. The afternoon gets even better: 4.9 ft east swell still at 19 seconds, energy climbing to 1550, and the wind turns cross-offshore from the northeast at 12 mph, giving clean conditions. That afternoon slot on Tuesday is probably our first real window – it’s not huge, but it’s clean and the swell’s got some push.
Now, Wednesday the 5th ramps up fast but gets messy. Morning sees 7.5 ft east swell, 19-second period, energy at 3588 – that’s strong energy. But the wind’s cross-shore from the north-northeast at 19 mph, lumpy cross-chop, so it’s not pretty. By the afternoon it’s 9.8 ft east at the same period, energy 5674, but the wind’s howling from the north at 25 mph – strong cross-shore with messy cross-chop. That’s only for experienced crew, and even then, it’s not gonna be clean.
Thursday the 6th is when things go nuts – and not in a good way for most. Morning brings 14.8 ft east swell at a very long 20-second period, energy a massive 17282. But the wind is a severe gale from the north-northwest at 53 mph, cross-onshore, totally blown out. Afternoon is worse: 23.0 ft northwest-northwest swell at 11 seconds, energy 19912, with hurricane-force winds from the northwest at 75 mph. This is dangerous, straight up. The reef will be handling that power, but only for the absolute elite, and even then the wind makes it a no-go for paddling.
Friday the 7th calms down wind-wise but the swell’s still massive. Morning has 18.0 ft west-northwest swell at 13 seconds, energy 10960, but the wind’s a storm-force south at 62 mph, cross-offshore – clean but insane. Afternoon is similar, 18.0 ft west swell at 13 seconds, energy 11172, wind a gale from the south-southeast at 43 mph, clean again but only for big-wave specialists.
Saturday the 8th starts to drop. Morning: 8.2 ft west-northwest swell at 12 seconds, energy 1747, with a fresh south-southeast breeze at 22 mph, cross-offshore and clean. Afternoon: 5.2 ft west swell at 11 seconds, energy 624, wind moderate from the south-southeast at 16 mph, still clean. That Saturday afternoon looks like a good option for experienced surfers – clean, dropping swell, manageable size.
Sunday the 9th goes small again: 2.6 ft west swell at
Short Range ForecastMostly dry. Warm (max 30°C on Fri afternoon, min 28°C on Fri night). Wind will be generally light. | Days 4-6 Weather SummaryModerate rain (total 15mm), heaviest on Wed night. Warm (max 30°C on Mon morning, min 28°C on Mon night). Winds increasing (light winds from the N on Mon morning, gales from the NNW by Wed night). | ||||||||||||||||||||
Friday 31 | Saturday 1 | Sunday 2 | Monday 3 | Tuesday 4 | Wednesday 5 | Thursday 6 | |||||||||||||||
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 10 | E 9 | E 9 | E 9 | E 9 | E 9 | E 19 | E 17 | ESE 16 | N 3 | N 3 | E 18 | E 18 | E 19 | E 18 | E 19 | E 19 | E 19 | E 20 | NNW 11 | W 12 |
Wave Graph | |||||||||||||||||||||
7 | 6 | 6 | 6 | 2 | 2 | 29 | 0 | 0 | 3 | 5 | 803 | 1044 | 1533 | 2345 | 3588 | 5674 | 8531 | 14443 | 10866 | 16928 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | glassy | on | cross-on | glassy | on | on | cross-off | cross-on | cross-on | cross | cross | cross-off | cross-off | cross | cross | cross-on | cross-on | cross-on | cross |
High Tide | 8:49PM2.03m | 8:23AM2.11m | 9:15PM2.06m | 9:02AM2.11m | 9:44PM2.06m | 9:44AM2.05m | 10:15PM2.05m | 10:30AM1.94m | 10:49PM2.01m | 11:26AM1.80m | 11:29PM1.96m | 12:40PM1.64m | 00:20AM1.89m | ||||||||
Low Tide | 2:23PM0.27m | 2:35AM0.83m | 2:54PM0.31m | 3:08AM0.74m | 3:26PM0.39m | 3:45AM0.67m | 4:00PM0.51m | 4:26AM0.63m | 4:37PM0.68m | 5:16AM0.63m | 5:17PM0.88m | 6:17AM0.64m | 6:08PM1.08m | ||||||||
5:52 | — | — | 5:52 | — | — | 5:54 | — | — | 5:54 | — | — | 5:54 | — | — | 5:54 | — | — | 5:56 | — | — | |
— | 7:16 | — | — | 7:15 | — | — | 7:15 | — | — | 7:15 | — | — | 7:14 | — | — | 7:14 | — | — | 7:13 | — | |
mm | — | — | — | — | — | — | — | — | — | 2 | — | 5 | — | 1 | — | — | — | 7 | 22 | 88 | 150 |
Temp °C | 29 | 30 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 30 | 30 | 29 | 30 | 30 | 29 | 30 | 30 | 30 | 28 | 29 | 30 |
Feels °C | 34 | 34 | 34 | 33 | 32 | 33 | 32 | 32 | 32 | 32 | 31 | 31 | 32 | 32 | 31 | 31 | 29 | 28 | 19 | 11 | 28 |
Swell 1 Height (m) Direction Period (s) | SW 8 | SW 8 | SW 8 | SW 8 | SW 8 | SW 8 | E 16 | E 17 | ESE 16 | ESE 15 | ESE 16 | E 18 | E 18 | E 19 | E 18 | E 19 | E 19 | E 19 | E 20 | ENE 18 | N 14 |
10 | 10 | 10 | 11 | 3 | 3 | 19 | 151 | 259 | 300 | 406 | 803 | 1044 | 1533 | 2345 | 3588 | 5674 | 8531 | 14443 | 7660 | 13313 | |
Swell 2 Height (m) Direction Period (s) | SE 9 | E 9 | E 9 | E 9 | E 9 | SE 9 | E 19 | ESE 9 | SW 7 | SW 7 | S 7 | SW 7 | S 9 | S 9 | SE 8 | — | — | — | — | NNE 11 | ENE 14 |
3 | 6 | 6 | 6 | 2 | 3 | 29 | 8 | 2 | 2 | 1 | 2 | 6 | 6 | 31 | — | — | — | — | 1386 | 258 | |
Swell 3 Height (m) Direction Period (s) | E 10 | SE 10 | SE 9 | SE 11 | SE 11 | E 9 | SW 8 | WSW 8 | S 7 | S 7 | — | SW 7 | — | — | — | — | — | — | — | — | — |
7 | 4 | 3 | 5 | 5 | 2 | 3 | 6 | 1 | 1 | — | 2 | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | N 3 | N 3 | N 4 | N 5 | N 5 | ESE 8 | ESE 8 | — | NNE 6 | N 9 | NNW 11 | W 12 |
— | — | — | — | — | — | — | — | — | 3 | 5 | 14 | 22 | 17 | 26 | 23 | — | 312 | 2839 | 10866 | 16928 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 760 | 865 | 984 | 1353 | 1408 | 652 | 24 | 15 | 27 | 27 | 36 | 36 | 27 | 27 | 10 | 796 | 735 | 608 | 796 | 735 | 735 |
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.











