Surf Forecasts:
Mainside surf forecast from 27 Aug 2026:
- Most powerful swell: Tuesday 1 Sep, 12PM (local time) - 15ft (4.5m), 10s period, E swell with 3,919 kJ wave energy.
Best Forecast Surf Conditions for Mainside this week:
The most powerful waves expected at Mainside in the next 16 days are 4.5m 10s and forecast to arrive on Tuesday (Sep 01) at 12PM. Winds are predicted to be onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 4.5m 11s period and expected on Tuesday (Sep 01) at 3PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 12PM (Tue 1st Sep) | 15ft (4.5m) 10s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s get straight to it. The next 16 days are pretty grim for Mainside – a real stretch of flat spells and messy conditions. There’s a small window of hope mid-period, but it’s marred by wind issues. Let's break it down.
We start with Thursday morning, the 27th of August. There’s a decent 10 ft west swell pumping, with a massive 1509 combined energy, but the wind is a fresh cross-shore from the SSW at 19 mph, making it lumpy. The afternoon gets a bit cleaner with an 8 ft WNW swell and cross-off southerly breeze, but it’s still marginal. Friday the 28th through the 30th, the swell drops fast – from 5 ft on Friday down to almost nothing by Sunday. Winds are offshore or clean, but the waves are just too small and weak to get excited about.
Then we hit a dead zone. Monday the 31st of August and Tuesday the 1st of September bring zero swell, risk of thunderstorms, and strong, messy winds. Wednesday the 2nd is also a bust for surf. This gap stretches from Sunday the 30th through to the end of the first week.
The next and only real standout comes on Thursday the 4th of September. A massive 16 ft WNW swell is forecast for the morning, with a combined energy of 5180 – that’s serious power. But watch out: the wind is a moderate cross-onshore from the NNW, creating lumpy, choppy conditions. This is big, powerful stuff, only for experts. The afternoon sees a 13 ft west swell with 3119 energy, but still cross-shore wind. This setup is way too big for beginners, and with the cross-shore wind, it might actually be more interesting for kite surfing than paddle surfing.
After that, the swell drops again. Friday the 5th and Saturday the 6th see 6 ft to 7 ft waves from the north, with clean cross-off winds on Saturday, but the scores are still marginal. Sunday the 7th onward, the swell fades into the 3 ft range and below, with more onshore or cross-shore wind and poor conditions.
Water temperature is 84°F, which is spot on average for this time of year.
The best on offer: If you’re an expert and brave, the Thursday morning (4th of September) at Mainside with that 16 ft WNW swell is the standout, but you’ll be fighting a lumpy cross-onshore wind. For the rest of us, it’s a long wait with very little action.
Rusty.
Short Range ForecastLight rain (total 2mm), mostly falling on Thu afternoon. Warm (max 29°C on Thu morning, min 27°C on Sat night). Mainly fresh winds. | Days 4-6 Weather SummaryHeavy rain (total 56mm), heaviest during Mon night. Warm (max 29°C on Sun morning, min 27°C on Sun night). Mainly strong winds. | ||||||||||||||||||||
Thursday 27 | Friday 28 | Saturday 29 | Sunday 30 | Monday 31 | Tuesday 1 | Wednesday 2 | |||||||||||||||
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) | W 10 | WNW 10 | WNW 10 | WNW 10 | W 10 | W 9 | W 8 | W 8 | ENE 12 | ENE 12 | ESE 10 | ENE 11 | ESE 10 | ESE 10 | ENE 10 | E 10 | SE 11 | NNE 7 | NW 8 | E 9 | E 10 |
Wave Graph  | |||||||||||||||||||||
 kJ | 1509 | 1130 | 803 | 410 | 184 | 110 | 49 | 18 | 30 | 14 | 0 | 13 | 0 | 0 | 1149 | 2457 | 0 | 17 | 3 | 356 | 250 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross-off | cross-off | cross-off | off | off | off | off | off | cross-off | cross-off | cross-off | cross-off | cross | cross | cross-on | cross-on | cross-on | on | cross-on | on |
High Tide | 7:28PM2.00m | 7:03AM2.08m | 7:50PM2.07m | 7:38AM2.16m | 8:14PM2.11m | 8:14AM2.20m | 8:39PM2.14m | 8:52AM2.18m | 9:06PM2.15m | 9:32AM2.11m | 9:36PM2.12m | 10:17AM1.97m | 10:08PM2.07m | ||||||||
Low Tide | 1:03PM0.38m | 1:16AM0.84m | 1:32PM0.34m | 1:43AM0.70m | 2:01PM0.34m | 2:13AM0.58m | 2:31PM0.39m | 2:45AM0.47m | 3:01PM0.49m | 3:20AM0.42m | 3:33PM0.63m | 4:00AM0.41m | 4:07PM0.80m | ||||||||
 |  |  |  | |  | | |  | | |  | | | | | | | | | | |
 | 6:05 | — | — | 6:05 | — | — | 6:07 | — | — | 6:07 | — | — | 6:07 | — | — | 6:07 | — | — | 6:07 | — | — |
 | — | 6:54 | — | — | 6:53 | — | — | 6:52 | — | — | 6:52 | — | — | 6:51 | — | — | 6:49 | — | — | 6:47 | — |
mm | — | 1 | 1 | — | — | — | — | — | — | — | — | 4 | 2 | 4 | 37 | 4 | 2 | 3 | 2 | 1 | — |
Temp °C | 29 | 29 | 28 | 29 | 29 | 28 | 29 | 29 | 28 | 29 | 29 | 27 | 28 | 28 | 27 | 28 | 28 | 28 | 28 | 28 | 28 |
Feels °C | 29 | 30 | 30 | 30 | 30 | 29 | 30 | 30 | 28 | 29 | 29 | 27 | 28 | 27 | 25 | 28 | 28 | 28 | 30 | 29 | 29 |
Swell 1 Height (m) Direction Period (s) | W 10 | WNW 10 | WNW 10 | WNW 10 | W 10 | W 9 | SW 9 | SW 9 | SW 8 | SW 9 | ESE 10 | ESE 10 | ESE 10 | ESE 10 | SW 10 | SW 10 | SW 10 | S 9 | S 11 | SSW 11 | SW 11 |
| kJ | 1509 | 1130 | 803 | 410 | 184 | 110 | 84 | 79 | 58 | 61 | 168 | 196 | 338 | 356 | 16 | 15 | 15 | 390 | 269 | 685 | 930 |
Swell 2 Height (m) Direction Period (s) | ESE 7 | ESE 7 | ESE 8 | SW 9 | SW 9 | SW 9 | W 8 | W 8 | SSW 10 | S 8 | SW 8 | SSW 9 | SSW 9 | SSW 9 | SSW 10 | SW 10 | — | SW 11 | SW 10 | SW 11 | E 10 |
| kJ | 18 | 17 | 32 | 79 | 75 | 81 | 49 | 18 | 31 | 34 | 44 | 65 | 28 | 16 | 18 | 4 | — | 94 | 188 | 368 | 250 |
Swell 3 Height (m) Direction Period (s) | SE 9 | SE 9 | E 12 | E 12 | S 7 | E 13 | S 8 | ENE 13 | ENE 12 | ENE 12 | S 9 | ENE 11 | SW 10 | SW 9 | WSW 10 | — | — | NNE 7 | NW 8 | NNW 8 | NNW 8 |
| kJ | 13 | 12 | 11 | 11 | 4 | 14 | 12 | 17 | 30 | 14 | 41 | 13 | 33 | 14 | 10 | — | — | 17 | 3 | 7 | 22 |
Wind waves Height (m) Direction Period (s) | S 8 | SSW 8 | S 9 | SE 6 | SE 6 | ESE 6 | SE 7 | SE 7 | ESE 7 | ESE 7 | E 4 | NE 4 | NE 5 | NE 6 | ENE 10 | E 10 | SE 11 | E 8 | ESE 7 | E 9 | S 11 |
| kJ | 20 | 155 | 122 | 106 | 91 | 130 | 158 | 136 | 83 | 71 | 6 | 13 | 102 | 146 | 1149 | 2457 | 5308 | 588 | 299 | 356 | 723 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 600 | 600 | 6 | 6 | 830 | 608 | 14 | 14 | 14 | 10 | 650 | 650 | 650 | 608 | 608 | 830 | 765 | 608 | 15 | 36 | 36 |
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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