Surf Forecasts:
Mainside surf forecast from 9 Sep 2026:
- Best quality surf: Thursday 10 Sep, 9PM (local time) - 4.5ft (1.4m), 9s period, N swell with cross-offshore winds.
- Most powerful swell: Thursday 10 Sep, 3PM (local time) - 5ft (1.5m), 9s period, N swell with 397 kJ wave energy.
- Next surfable swell (1★+): Thursday 10 Sep, 9PM (local time) - 4.5ft (1.4m), 9s 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 9PM. The primary swell is predicted to be 1.4m and 9s period. 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 1.5m 9s and forecast to arrive on Thursday (Sep 10) at 3PM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 6s period and expected on Sunday (Sep 13) at 12PM.
| Wave Type | Time (JST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 9PM (Thu 10th Sep) | 4.5ft (1.4m) 9s |
| Best Surf | 9PM (Thu 10th Sep) | 4.5ft (1.4m) 9s |
| Most Powerful | 3PM (Thu 10th Sep) | 5ft (1.5m) 9s |
Table - best surf conditions forecast for Mainside over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s cut through the noise and see what’s on the cards for Mainside over the next couple of weeks.
Straight up, it’s a pretty grim start. We’re looking at a solid gap with no real surf on offer for the first few days. The 10th and most of the 11th are a write-off with poor conditions and only tiny lumps. The first real chance to get wet comes Friday morning, the 11th, but don’t get your hopes up – it’s small and ordinary.
The standout window, and the only one worth getting excited about, is actually a long way off. I’m talking about Tuesday the 22nd and Wednesday the 23rd. A serious pulse of energy shows up, with a massive combined swell energy reading in the thousands (4017 on Tuesday morning, 3180 Tuesday afternoon). That’s a strong, powerful groundswell from the east, with a very long period of 16 seconds on Tuesday morning. This is big, heavy water – over 8 feet for the Tuesday morning session – and that’s expert territory only. The wind on Tuesday is a full-on onshore gale, so expect it to be a challenging, messy beast. By Wednesday, the swell drops a touch to 7 feet and 6 feet, and the wind swings more cross-shore, but it’s still a fresh breeze and lumpy.
For the average punter, it’s not looking great. The best bet for a clean, manageable wave might be Friday afternoon, the 11th, with a gentle offshore wind and 3 feet of swell from the NNW. It’s tiny, but glassy. That’s about as good as it gets before the big storm.
The water temperature is pretty standard for this time of year, nothing unusual to report.
So, my pick of the bunch? If you’re a seasoned charger and you’ve got your big-wave gear ready, keep an eye on that Tuesday the 22nd and Wednesday the 23rd. The energy is undeniably there, but the wind is a major factor. It’s a promising but uncertain long-range bet. For everyone else, it’s a waiting game. The forecast can change, but right now, there’s not much to get the stoke levels up.
Rusty.
Short Range ForecastLight rain (total 6mm), mostly falling on Thu night. Warm (max 29°C on Fri afternoon, min 27°C on Wed night). Wind will be generally light. | Days 5-7 Weather SummaryModerate rain (total 18mm), heaviest on Mon afternoon. Warm (max 29°C on Mon morning, min 27°C on Sat night). Wind will be generally light. | ||||||||||||||||||
Thursday 10 | Friday 11 | Saturday 12 | Sunday 13 | Monday 14 | Tuesday 15 | ||||||||||||||
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 8 | N 9 | N 9 | N 9 | N 9 | NNW 8 | N 8 | N 7 | N 7 | E 14 | E 14 | E 6 | E 13 | E 13 | E 13 | E 13 | E 13 | E 9 | E 9 |
Wave Graph  | |||||||||||||||||||
 kJ | 160 | 306 | 397 | 325 | 181 | 109 | 57 | 54 | 36 | 36 | 35 | 50 | 32 | 31 | 14 | 31 | 14 | 83 | 87 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | cross | cross | off | off | off | off | off | off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | off | glassy | cross-off |
High Tide | 6:26AM2.14m | 7:12PM2.08m | 7:08AM2.21m | 7:38PM2.13m | 7:46AM2.23m | 8:04PM2.16m | 8:22AM2.19m | 8:30PM2.17m | 8:56AM2.10m | 8:54PM2.14m | 9:30AM1.97m | 9:19PM2.09m | |||||||
Low Tide | 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 | 2:56PM0.61m | 3:19AM0.37m | 3:20PM0.75m | |||||||
 |  | |  |  | | | | | |  | |  | | | | | | | |
 | — | 6:11 | — | — | 6:11 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — | 6:13 | — | — |
 | 6:40 | — | 6:39 | — | — | 6:38 | — | — | 6:37 | — | — | 6:36 | — | — | 6:35 | — | — | 6:34 | — |
mm | — | — | — | 3 | 2 | 1 | — | — | — | — | 1 | 2 | — | — | 7 | 4 | — | 4 | 7 |
Temp °C | 27 | 28 | 28 | 28 | 28 | 29 | 28 | 29 | 29 | 27 | 28 | 28 | 27 | 29 | 28 | 27 | 29 | 29 | 28 |
Feels °C | 28 | 31 | 31 | 33 | 32 | 32 | 31 | 31 | 31 | 30 | 30 | 30 | 29 | 31 | 30 | 29 | 34 | 34 | 32 |
Swell 1 Height (m) Direction Period (s) | ESE 9 | N 9 | N 9 | N 9 | N 9 | NNW 8 | N 8 | N 7 | N 7 | N 7 | N 6 | N 6 | ESE 8 | ESE 9 | ESE 9 | ESE 9 | ESE 9 | E 9 | E 9 |
| kJ | 17 | 306 | 397 | 325 | 181 | 109 | 57 | 54 | 36 | 23 | 12 | 11 | 47 | 101 | 110 | 110 | 110 | 83 | 87 |
Swell 2 Height (m) Direction Period (s) | S 7 | ESE 9 | SE 9 | ESE 9 | ESE 9 | ESE 8 | E 15 | E 14 | SE 6 | S 7 | E 14 | E 14 | N 6 | N 5 | E 13 | E 13 | N 4 | NNW 7 | N 6 |
| kJ | 4 | 17 | 20 | 16 | 25 | 24 | 19 | 35 | 19 | 9 | 35 | 36 | 11 | 5 | 14 | 31 | 3 | 37 | 18 |
Swell 3 Height (m) Direction Period (s) | SW 8 | S 7 | SW 8 | S 7 | E 15 | E 15 | WNW 6 | SE 10 | E 14 | E 14 | S 7 | S 6 | E 13 | E 13 | S 7 | SW 8 | E 13 | E 15 | E 14 |
| kJ | 3 | 4 | 3 | 4 | 17 | 17 | 3 | 4 | 36 | 36 | 4 | 3 | 32 | 31 | 1 | 2 | 14 | 19 | 16 |
Wind waves Height (m) Direction Period (s) | N 8 | — | — | — | SE 4 | SSE 4 | ESE 6 | SE 6 | E 3 | E 4 | E 6 | E 6 | ENE 4 | — | NE 3 | NNE 4 | — | — | ESE 3 |
| kJ | 160 | — | — | — | 5 | 4 | 25 | 38 | 2 | 9 | 32 | 50 | 7 | — | 5 | 5 | — | — | 1 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 976 | 9 | 10 | 0 | 0 | 0 | 0 | 0 | 0 | 13 | 650 | 10 | 13 | 608 | 27 | 27 | 27 | 0 | 0 |
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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