Surf Forecasts:
Mainside surf forecast from 7 Sep 2026:
- Best quality surf: Thursday 10 Sep, 3PM (local time) - 4.5ft (1.4m), 8s period, N swell with cross-offshore winds.
- Most powerful swell: Tuesday 8 Sep, 6PM (local time) - 6ft (1.9m), 8s period, NNW swell with 494 kJ wave energy.
- Next surfable swell (1★+): Thursday 10 Sep, 3PM (local time) - 4.5ft (1.4m), 8s period with N 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 (Sep 10) at 3PM. The primary swell is predicted to be 1.4m and 8s period with a secondary swell of 1.1m and 8s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Mainside in the next 16 days are 1.9m 8s and forecast to arrive on Tuesday (Sep 08) at 6PM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.4m 5s period and expected on Monday (Sep 14) at 12PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3PM (Thu 10th Sep) | 4.5ft (1.4m) 8s |
| Best Surf | 3PM (Thu 10th Sep) | 4.5ft (1.4m) 8s |
| Most Powerful | 6PM (Tue 8th Sep) | 6ft (1.9m) 8s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Alright, Rusty here, giving you the lowdown for Mainside.
First few days are a bust. Monday the 7th through Wednesday the 9th, we’ve got a fresh cross-onshore breeze making a mess of things. Swell is around 5 to 6 feet from the NNW, but the period is short and the wind is just junk. Water temp is about 84°, pretty normal for now.
The first real chance to paddle out comes on Thursday the 10th. The wind backs off to a gentle cross-offshore from the NE, and the swell settles to 5 feet from the north. The combined energy is moderate (434), and the surface cleans up. It’s surfable, but nothing special.
The standout is Friday the 11th morning. Offshore wind from the ESE at 12 mph, swell at 4 feet from the north, period 9 seconds. Combined energy is moderate (202). This is your cleanest window. It’s a reef break, so that longer period will give you some nice lines. Crowds are possible, so get there early.
After that, the swell drops fast. Saturday the 12th is down to 2 feet, and by the afternoon it’s tiny. We get a few small, clean days through the middle of the week. The next pulse is Monday the 14th afternoon, with offshore wind from the E at 16 mph, swell 5 feet from the east, period 7 seconds. Combined energy is moderate (244). It’s okay, but not a classic.
Looking further out, Monday the 21st morning shows a pulse of 6 feet from the NNE, but the wind is cross-shore and the period is short (9 seconds). Combined energy is strong (624), but it’ll be choppy and messy. That size is for experienced surfers only.
Best bet: Friday the 11th morning. Clean, offshore, and a fun size. The rest is a waiting game.
Rusty.
Short Range ForecastLight rain (total 5mm), mostly falling on Thu morning. Warm (max 28°C on Mon afternoon, min 27°C on Mon night). Mainly fresh winds. | Days 5-7 Weather SummaryModerate rain (total 10mm), heaviest on Thu afternoon. Warm (max 28°C on Thu afternoon, min 27°C on Thu night). Wind will be generally light. | |||||||||||||||||||
Mon 7 | Tuesday 8 | Wednesday 9 | Thursday 10 | Friday 11 | Saturday 12 | Sunday 13 | ||||||||||||||
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) | NNW 8 | NNW 9 | NNW 8 | NNW 9 | NNW 8 | N 8 | N 8 | N 7 | N 8 | N 8 | N 9 | N 9 | N 8 | N 8 | N 8 | N 7 | E 14 | E 7 | E 7 | E 7 |
Wave Graph  | ||||||||||||||||||||
 kJ | 460 | 427 | 445 | 466 | 308 | 266 | 227 | 155 | 253 | 273 | 334 | 185 | 144 | 58 | 57 | 39 | 36 | 103 | 117 | 142 |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | cross-on | cross | cross | cross | cross | cross | cross-off | off | off | off | off | off | off | cross-off | cross-off | cross-off | cross-off |
High Tide | 5:34PM1.77m | 4:36AM1.86m | 6:12PM1.90m | 5:37AM2.01m | 6:43PM2.00m | 6:26AM2.14m | 7:12PM2.08m | 7:08AM2.21m | 7:38PM2.13m | 7:46AM2.23m | 8:04PM2.16m | 8:22AM2.19m | 8:30PM2.17m | |||||||
Low Tide | 11:02PM1.18m | 11:31AM0.41m | 11:53PM0.98m | 12:17PM0.33m | 00:33AM0.78m | 12:56PM0.30m | 1:08AM0.61m | 1:30PM0.32m | 1:42AM0.47m | 2:01PM0.39m | 2:15AM0.39m | 2:29PM0.49m | 2:47AM0.36m | |||||||
 |  | | | |  | | | | |  | | | | | | | | | | |
 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:11 | — | — | 6:13 | — | — | 6:13 | — | — |
 | 6:43 | — | — | 6:42 | — | — | 6:40 | — | — | 6:39 | — | — | 6:38 | — | — | 6:37 | — | — | 6:36 | — |
mm | — | — | — | — | — | 1 | — | — | 4 | 6 | 2 | 1 | 1 | — | — | — | — | — | 1 | — |
Temp °C | 28 | 28 | 28 | 28 | 27 | 27 | 27 | 27 | 27 | 28 | 28 | 28 | 28 | 27 | 28 | 28 | 27 | 28 | 28 | 27 |
Feels °C | 28 | 29 | 28 | 28 | 27 | 27 | 27 | 29 | 29 | 32 | 32 | 31 | 30 | 29 | 29 | 29 | 28 | 29 | 29 | 29 |
Swell 1 Height (m) Direction Period (s) | SSW 8 | NE 10 | S 8 | S 8 | S 8 | S 8 | S 8 | N 7 | N 8 | N 8 | N 9 | N 9 | N 8 | N 8 | N 8 | SE 7 | SSE 9 | S 11 | S 10 | SSE 9 |
| kJ | 14 | 14 | 11 | 5 | 5 | 5 | 4 | 155 | 253 | 273 | 334 | 185 | 144 | 58 | 57 | 37 | 61 | 61 | 46 | 25 |
Swell 2 Height (m) Direction Period (s) | E 8 | E 8 | SW 8 | SSW 8 | SW 9 | SW 8 | ESE 10 | ESE 10 | E 9 | ESE 9 | SE 9 | ESE 8 | ESE 8 | NW 5 | E 14 | N 7 | NNW 6 | N 6 | N 6 | E 13 |
| kJ | 12 | 11 | 10 | 6 | 3 | 3 | 10 | 9 | 15 | 17 | 20 | 14 | 23 | 7 | 35 | 39 | 14 | 12 | 6 | 32 |
Swell 3 Height (m) Direction Period (s) | NE 10 | SW 8 | E 8 | NE 8 | E 9 | ESE 10 | SW 8 | E 9 | S 7 | S 7 | E 16 | E 15 | E 15 | E 15 | SSE 12 | S 10 | E 14 | E 14 | E 14 | N 6 |
| kJ | 33 | 10 | 6 | 3 | 6 | 10 | 3 | 6 | 4 | 4 | 5 | 17 | 17 | 19 | 14 | 55 | 36 | 35 | 36 | 6 |
Wind waves Height (m) Direction Period (s) | NNW 8 | NNW 9 | NNW 8 | NNW 9 | NNW 8 | N 8 | N 8 | — | NE 7 | N 8 | SE 6 | SE 5 | — | ESE 7 | ESE 7 | E 4 | E 5 | E 7 | E 7 | E 7 |
| kJ | 460 | 427 | 445 | 466 | 308 | 266 | 227 | — | 2 | 161 | 32 | 13 | — | 48 | 73 | 10 | 35 | 103 | 117 | 142 |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 650 | 36 | 650 | 650 | 36 | 650 | 756 | 608 | 27 | 0 | 0 | 0 | 0 | 0 | 0 | 10 | 10 | 1 | 1 | 1 |
Best forecast wave conditions in Okinawa | ||||||||||||||||||||
Best forecast wave conditions in Japan | ||||||||||||||||||||
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The surf report / weather widget below is available to embed on third party websites free of charge and provides a summary of our Mainside surf forecast. Simply grab the html code snippet that we provide and paste it into your own site. You can choose your preferred language and metric/imperial units for the surf forecast feed to suit users of your site. Click here to get the code.
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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