Surf Forecasts:
Mainside surf forecast from 13 Aug 2026:
- Best quality surf: Thursday 20 Aug, 3AM (local time) - 3.5ft (1.1m), 6s period, E swell with offshore winds.
- Most powerful swell: Thursday 20 Aug, 3AM (local time) - 3.5ft (1.1m), 6s period, E swell with 97 kJ wave energy.
- Next surfable swell (1★+): Thursday 20 Aug, 3AM (local time) - 3.5ft (1.1m), 6s 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 20) at 3AM. The primary swell is predicted to be 1.1m and 6s period. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Mainside in the next 16 days are 1.1m 6s and forecast to arrive on Thursday (Aug 20) at 3AM. Winds are predicted to be offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.2m 9s period and expected on Thursday (Aug 20) at 9PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3AM (Thu 20th Aug) | 3.5ft (1.1m) 6s |
| Best Surf | 3AM (Thu 20th Aug) | 3.5ft (1.1m) 6s |
| Most Powerful | 3AM (Thu 20th Aug) | 3.5ft (1.1m) 6s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s be straight with you – the next week and a half is a real flat spell for Mainside. We’re looking at tiny, weak waves for days on end, so don’t be in a rush to get the wettie on.
The first proper surf we can talk about doesn’t show up until Tuesday, the 25th of August. That’s a big gap of about ten days with nothing worth paddling out for. When that Tuesday morning rolls around, we’ll see a pulse of 5 ft swell from the East with a very long period of 15 seconds. That’s proper groundswell energy, with the combined energy clocking in at a strong 1104. The direction is a cross-on from the WSW at 9 mph, so it’ll be a bit bumpy. At that size, it’s pushing into expert territory, and the long period means it’ll wall up best on the reef, but the wind isn’t doing us any favours for a clean face. The water temperature is 84°F, which is about average for this time of year.
Honestly, the standout window is narrow. The best of a tricky bunch might be the Wednesday morning of the 26th. The swell drops to 3 ft, but it’s still a solid 13-second period from the ENE. The combined energy is moderate at 408. The wind is still cross-on from the WSW at 9 mph, which is a bit of a pain, but it’s cleaner than the day before. The surf will be small, so it’s better for a fun log on the reef if you can find a clean corner.
Thursday the 27th has similar small stuff, with 3 ft from the ENE and a 13-second period, but the combined energy drops to 244, and the wind switches to a cross-shore from the SW. It’s marginal, with a bit of chop.
So, to put it simply: take the first two weeks off. You’ve got a small window of average, low-quality surf around the 25th and 26th, but it’s not a scene to set your alarm for. The crowd profile at Mainside is “sometimes,” so you might see a few other frothers out there, but on this offering, it won’t be packed.
Keep an eye on the sky, but for now, it’s a waiting game.
Rusty.
Short Range ForecastLight rain (total 9mm), mostly falling on Sat afternoon. Warm (max 29°C on Fri afternoon, min 27°C on Thu night). Wind will be generally light. | Days 5-7 Weather SummarySome drizzle, heaviest during Mon afternoon. Warm (max 29°C on Tue afternoon, min 26°C on Sun night). Mainly fresh winds. | ||||||||||||||||||
Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | Wednesday 19 | ||||||||||||||
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) | N 7 | N 7 | ENE 10 | W 6 | ENE 11 | ENE 11 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | SW 9 | ENE 9 | E 4 | E 6 | E 10 |
Wave Graph | |||||||||||||||||||
14 | 16 | 9 | 7 | 23 | 23 | 20 | 20 | 20 | 19 | 20 | 19 | 19 | 18 | 0 | 17 | 0 | 79 | 2 | |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | glassy | glassy | off | off | off | off | off | off | off | cross-off | off | off | cross-off | off | cross-off | cross-off | cross-off | off |
High Tide | 7:57AM2.27m | 8:42PM2.15m | 8:37AM2.24m | 9:11PM2.15m | 9:15AM2.15m | 9:39PM2.13m | 9:54AM2.02m | 10:07PM2.08m | 10:34AM1.85m | 10:36PM2.01m | 11:19AM1.67m | 11:07PM1.91m | |||||||
Low Tide | 2:03AM0.69m | 2:27PM0.21m | 2:39AM0.60m | 3:00PM0.32m | 3:15AM0.54m | 3:31PM0.46m | 3:52AM0.54m | 4:00PM0.62m | 4:31AM0.58m | 4:28PM0.80m | 5:13AM0.66m | 4:55PM0.98m | |||||||
— | 6:00 | — | — | 6:00 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — | 6:01 | — | — | |
7:07 | — | 7:07 | — | — | 7:06 | — | — | 7:05 | — | — | 7:04 | — | — | 7:02 | — | — | 7:01 | — | |
mm | — | — | — | — | — | 4 | 5 | — | — | — | — | 1 | — | — | — | — | — | — | 1 |
Temp °C | 28 | 28 | 29 | 28 | 29 | 29 | 27 | 28 | 28 | 27 | 28 | 28 | 27 | 28 | 29 | 27 | 28 | 29 | 27 |
Feels °C | 33 | 33 | 33 | 33 | 34 | 33 | 30 | 30 | 30 | 29 | 30 | 29 | 29 | 29 | 30 | 29 | 28 | 30 | 29 |
Swell 1 Height (m) Direction Period (s) | SW 8 | SSW 8 | SSW 8 | SW 9 | SW 8 | SSW 8 | SSW 9 | SSW 9 | SW 9 | SSW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SSW 9 | SSW 9 | SSW 9 | S 9 |
57 | 113 | 78 | 62 | 58 | 54 | 99 | 94 | 62 | 103 | 79 | 77 | 81 | 49 | 36 | 52 | 16 | 16 | 15 | |
Swell 2 Height (m) Direction Period (s) | S 9 | N 7 | N 6 | S 8 | S 8 | ENE 11 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | ENE 10 | S 10 | S 10 | ENE 9 | SW 8 | SW 9 | SW 10 |
25 | 16 | 7 | 21 | 20 | 23 | 20 | 20 | 20 | 19 | 20 | 19 | 19 | 28 | 16 | 17 | 11 | 12 | 15 | |
Swell 3 Height (m) Direction Period (s) | N 7 | ENE 10 | ENE 10 | W 6 | ENE 11 | SSE 8 | W 6 | SE 11 | S 8 | SE 11 | SE 11 | SE 11 | SE 10 | ENE 10 | SE 10 | SE 10 | SE 10 | ENE 9 | E 10 |
14 | 10 | 9 | 7 | 23 | 14 | 2 | 5 | 12 | 4 | 4 | 4 | 4 | 18 | 4 | 4 | 4 | 17 | 2 | |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | ESE 4 | ESE 5 | ESE 4 | ESE 4 | ESE 5 | ESE 5 | E 4 | E 5 | E 4 | E 6 | E 4 | E 6 | E 6 |
— | — | — | — | — | — | 11 | 15 | 12 | 7 | 17 | 14 | 7 | 14 | 18 | 52 | 31 | 79 | 71 | |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 10 | 10 | 10 | 10 | 10 | 10 | 14 | 14 | 14 | 14 | 10 | 14 | 14 | 10 | 10 | 10 | 10 | 650 | 618 |
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.











