
Surf Forecasts:
Nanwan Beach (South Bay) surf forecast from 9 Aug 2026:
- Best quality surf: Sunday 9 Aug, 5PM (local time) - 11ft (3.5m), 9s period, SW swell with cross-offshore winds.
- Most powerful swell: Monday 10 Aug, 5AM (local time) - 11ft (3.5m), 10s period, SW swell with 2,291 kJ wave energy.
- Next surfable swell (1★+): Sunday 9 Aug, 5PM (local time) - 11ft (3.5m), 9s period with SW swell.
Best Forecast Surf Conditions for Nanwan Beach (South Bay) this week:
The surf forecast for Nanwan Beach (South Bay) over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Sunday (Aug 09) at 5PM. The primary swell is predicted to be 3.5m and 9s period with a secondary swell of 0.2m and 10s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Nanwan Beach (South Bay) in the next 16 days are 3.5m 10s and forecast to arrive on Monday (Aug 10) at 5AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.7m 14s period and expected on Tuesday (Aug 11) at 2AM.
| Wave Type | Time (CST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 5PM (Sun 9th Aug) | 11ft (3.5m) 9s |
| Best Surf | 5PM (Sun 9th Aug) | 11ft (3.5m) 9s |
| Most Powerful | 5AM (Mon 10th Aug) | 11ft (3.5m) 10s |
Table - best surf conditions forecast for Nanwan Beach (South Bay) over the next 16 days.
The Lowdown
Alright, folks, Rusty here again, giving you the same lowdown in feet and miles per hour, because that’s how some of us measure it.
The only game in town is Nanwan Beach (South Bay). It’s a beach and reef setup, pretty consistent, but we’ve got a wild ride ahead.
Water temp is a balmy 85°, just about average for the season, so no surprises there.
Right off the bat, it’s ugly. We’ve got a big groundswell pumping in – 12 feet from the SW, with strong to very strong wave energy (1621 is the reading). The problem is a howling 31 mph wind from the WSW, creating a cross-off mess. The report calls it “poor surf conditions.” Zero rating. Sunday through Tuesday morning is just a repeat: big, powerful, but choppy and ugly. The wind stays in the 19-31 mph range with a lot of cross-shore cleaning. If you’re a surfer, stay on the beach. The kite surfers will be having a field day.
Things calm down a bit starting Wednesday the 12th. The swell drops to about 7 feet from the SW (energy down to 752), and the wind eases to a cross-off 16-19 mph from the west. The water clears up, but it’s still called “marginal.” Thursday and Friday the 13th and 14th are more of the same: 7-foot SW swell, cross-off wind, but still poor or marginal. The wave period is a short 9 seconds, so the waves will be close together and a bit weak.
But hold on. Sunday the 16th and Monday the 17th are the real deal. On the 16th, we’ve got a 7-foot SW swell (energy 800), and the wind swings to a light 9 mph from the NW – nice and clean cross-off. Then on the 17th, the wind drops to 6 mph from the WNW. The report says “expect very good surf conditions.” That’s the best we’ve got. For a beach and reef break, a clean 7-foot SW swell with moderate energy and light wind is prime. The waves will have some punch. Just watch for the crowds – it says “often,” so you won’t be alone. Get there early.
The second week goes downhill. Swell drops to 4 to 5 feet from the 19th to the 21st, but the wind swings to a nasty 22-28 mph from the NE and ENE. It might look clean on paper, but the scores are zero. It’s all wind and no shape. That’s a solid three-day gap with nothing to ride.
Then, there’s a late shot on Sunday the 23rd of August. The swell comes back to 7 feet from the SW, the wind goes light from the NE at 9 mph (cross-off), and the energy jumps to 959. The forecast says “expect very good surf conditions” again. It’s over a week out, so keep your fingers crossed, but it looks promising. Then Monday the 24th slides back to a 6-foot swell with a stronger 22 mph westerly wind, bringing it back to marginal.
So here’s the takeaway: Sunday the 16th and Sunday the 23rd of August are the days you want. Clean 7-foot SW swell, light offshore or cross-off wind, moderate energy. The rest of the 16-day window is either too big and windy, or too small and windy. It’s a waiting game, but those two windows are worth waiting for.
Rusty.
Short Range ForecastHeavy rain (total 49mm), heaviest during Sun morning. Warm (max 30°C on Sun morning, min 28°C on Mon night). Winds decreasing (strong winds from the WSW on Sun morning, moderate winds from the WSW by Tue night). | Days 4-6 Weather SummaryHeavy rain (total 42mm), heaviest during Fri night. Warm (max 29°C on Wed morning, min 28°C on Wed morning). Mainly fresh winds. | ||||||||||||||||||||
Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | |||||||||||||||
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) | SW 9 | SW 9 | SW 10 | SW 9 | SW 10 | SW 10 | SW 9 | SW 9 | SW 10 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 | SW 9 |
Wave Graph | |||||||||||||||||||||
1608 | 1874 | 2203 | 1967 | 1564 | 1824 | 1080 | 918 | 958 | 727 | 718 | 668 | 567 | 625 | 573 | 657 | 695 | 770 | 711 | 753 | 861 | |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross-off | cross | cross | cross | cross | cross | cross | cross | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross-off | cross | cross-off | cross-off | cross |
High Tide | 6:13PM0.51m | 4:05AM1.24m | 6:39PM0.52m | 5:05AM1.31m | 7:05PM0.54m | 5:59AM1.35m | 7:32PM0.57m | 6:48AM1.35m | 7:59PM0.62m | 7:33AM1.28m | 8:26PM0.69m | 8:15AM1.17m | 8:55PM0.76m | ||||||||
Low Tide | 11:21AM0.09m | 8:02PM0.49m | 12:12PM0.02m | 9:36PM0.46m | 12:56PM-0.02m | 10:47PM0.40m | 1:35PM-0.01m | 11:46PM0.34m | 2:10PM0.03m | 00:41AM0.30m | 2:39PM0.10m | 1:33AM0.28m | 3:05PM0.18m | 2:26AM0.28m | |||||||
5:31 | — | — | 5:31 | — | — | 5:33 | — | — | 5:33 | — | — | 5:33 | — | — | 5:33 | — | — | 5:33 | — | — | |
— | 6:31 | — | — | 6:30 | — | — | 6:30 | — | — | 6:30 | — | — | 6:29 | — | — | 6:28 | — | — | 6:28 | — | |
mm | 4 | 5 | 9 | 3 | 4 | 9 | 5 | 3 | 7 | 3 | 1 | 2 | 3 | 2 | 4 | 7 | 7 | 13 | 10 | 9 | 25 |
Temp °C | 30 | 30 | 29 | 30 | 30 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 29 | 28 |
Feels °C | 27 | 28 | 27 | 29 | 30 | 30 | 30 | 30 | 32 | 30 | 30 | 31 | 30 | 29 | 31 | 31 | 30 | 32 | 31 | 31 | 31 |
Swell 1 Height (m) Direction Period (s) | NE 13 | NE 12 | NE 11 | ENE 15 | ENE 15 | ENE 14 | ENE 13 | SW 9 | ENE 12 | SW 9 | SW 9 | ENE 12 | ENE 11 | ENE 11 | SW 9 | SW 9 | ENE 10 | SW 9 | ENE 10 | SW 9 | ENE 11 |
178 | 71 | 18 | 73 | 123 | 201 | 181 | 918 | 117 | 727 | 718 | 78 | 47 | 46 | 573 | 657 | 19 | 770 | 19 | 753 | 11 | |
Swell 2 Height (m) Direction Period (s) | SE 10 | SSE 10 | ENE 15 | SE 10 | SE 10 | SE 10 | SE 10 | ENE 13 | SE 9 | ENE 12 | ENE 12 | SE 8 | SE 8 | SE 8 | NE 10 | NE 10 | SE 8 | ENE 10 | SE 11 | ENE 10 | ESE 10 |
4 | 9 | 21 | 28 | 25 | 47 | 46 | 178 | 36 | 113 | 78 | 16 | 10 | 11 | 26 | 25 | 3 | 19 | 5 | 10 | 10 | |
Swell 3 Height (m) Direction Period (s) | E 11 | ENE 15 | SSE 10 | NNE 10 | NE 9 | — | N 10 | SE 9 | — | SE 8 | SE 8 | NE 8 | N 8 | N 8 | SE 8 | SSE 8 | E 12 | SSE 8 | NE 7 | SE 11 | ESE 10 |
9 | 22 | 10 | 11 | 3 | — | 2 | 42 | — | 25 | 25 | 3 | 1 | 1 | 9 | 7 | 3 | 6 | 2 | 5 | 10 | |
Wind waves Height (m) Direction Period (s) | SW 9 | SW 9 | SW 10 | SW 9 | SW 10 | SW 10 | SW 9 | — | SW 10 | — | — | SW 9 | SW 9 | SW 9 | — | — | SW 9 | — | SW 9 | — | SW 9 |
1608 | 1874 | 2203 | 1967 | 1564 | 1824 | 1080 | — | 958 | — | — | 668 | 567 | 625 | — | — | 695 | — | 711 | — | 861 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 148 | 316 | 316 | 148 | 148 | 148 | 348 | 348 | 148 | 316 | 42 | 316 | 375 | 375 | 348 | 639 | 859 | 14 | 42 | 14 | 14 |
Best forecast wave conditions in South Taiwan | |||||||||||||||||||||
Best forecast wave conditions in Taiwan | |||||||||||||||||||||
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Information about the Nanwan Beach (South Bay) Surf forecast
The above surf forecast table for Nanwan Beach (South Bay) provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Nanwan Beach (South Bay) can be found by selecting the local surf guide option on the grey menu. Our Nanwan Beach (South Bay) 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 (Nanwan Beach (South Bay)) 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 Nanwan Beach (South Bay) 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.











