Surf Forecasts:
Nanwan Beach (South Bay) surf forecast from 18 Aug 2026:
- Best quality surf: Saturday 22 Aug, 8AM (local time) - 11ft (3.5m), 10s period, SW swell with cross-shore winds.
- Most powerful swell: Friday 21 Aug, 8AM (local time) - 13ft (4.0m), 10s period, SW swell with 2,721 kJ wave energy.
- Next surfable swell (1★+): Saturday 22 Aug, 8AM (local time) - 11ft (3.5m), 10s 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 Saturday (Aug 22) at 8AM. The primary swell is predicted to be 3.5m and 10s period with a secondary swell of 0.2m and 10s. The wind is predicted to be cross-shore as the swell arrives.
The most powerful waves expected at Nanwan Beach (South Bay) in the next 16 days are 4.0m 10s and forecast to arrive on Friday (Aug 21) at 8AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.6m 6s period and expected on Tuesday (Aug 18) at 11PM.
| Wave Type | Time (CST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 8AM (Sat 22nd Aug) | 11ft (3.5m) 10s |
| Best Surf | 8AM (Sat 22nd Aug) | 11ft (3.5m) 10s |
| Most Powerful | 8AM (Fri 21st Aug) | 13ft (4.0m) 10s |
Table - best surf conditions forecast for Nanwan Beach (South Bay) over the next 16 days.
The Lowdown
Alright, let’s break it down in feet and miles. The first few days are a total loss – stormy, windy, and the surf is just junk. You’ll be waiting until the end of the week before anything clean shows up. The water temp is 85°F, which is dead average for this time of year, no surprises there.
The first real chance to get a wave is Sunday, 23 August. Nanwan Beach (South Bay) will have a clean cross-offshore breeze from the WNW. The swell is a solid 8ft from the SW with a 9-second period and moderate energy. It’s not the best, but it’s rideable. The real standout is Monday, 24 August. That morning the wind goes glassy – dead calm – and the swell is a clean 7ft from the SW with a 9-second period. The combined energy is moderate, and the conditions are described as “expect very good surf.” This is the pick of the run. It’s a bit big for beginners, but for the intermediates, it’s going to be a beauty. The afternoon stays clean with a light cross-offshore breeze.
Then in the second week, from Tuesday, 25 August, a new, very long-period groundswell from the E shows up, with periods of 16 and 17 seconds and very strong energy (over 2000). The problem is the wind turns cross-shore, making it a bit lumpy for a beach break. The best of that late run is Thursday, 27 August morning, with a gentle cross-shore breeze and 7ft of 16-second E swell and very strong energy. It’s a promising option but a long-range call. After that, the swell drops and the wind turns onshore again.
So, the one to circle on the calendar is Monday, 24 August at Nanwan Beach (South Bay) – glassy, clean, and a solid 7ft SW swell. That’s the wave to chase.
Rusty
Short Range ForecastHeavy rain (total 60mm), heaviest during Thu morning. Warm (max 30°C on Tue morning, min 27°C on Wed night). Winds decreasing (fresh winds from the NE on Tue morning, light winds from the SSW by Wed night). | Days 4-6 Weather SummaryHeavy rain (total 52mm), heaviest during Fri morning. Warm (max 29°C on Sun morning, min 28°C on Fri morning). Winds decreasing (fresh winds from the SW on Fri night, light winds from the WNW by Sun night). | ||||||||||||||||||||
Tuesday 18 | Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | |||||||||||||||
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 8 | SSW 8 | SSW 9 | SSW 8 | SSW 8 | SSW 10 | SSW 9 | SSW 9 | SSW 10 | SW 10 | SW 10 | SW 10 | SW 10 | SW 11 | SW 10 | SW 9 | SW 9 | SW 9 | SW 9 | SW 8 | SW 9 |
Wave Graph  | |||||||||||||||||||||
 kJ | 196 | 202 | 280 | 222 | 188 | 838 | 948 | 1158 | 2420 | 2721 | 2629 | 2382 | 2074 | 2434 | 1790 | 1119 | 911 | 931 | 695 | 534 | 563 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | cross | cross | cross | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross | cross | cross | cross-off | cross-off | cross-off | glassy | cross-off | off |
High Tide | 10:10AM0.71m | 10:34PM0.92m | 10:51AM0.58m | 11:17PM0.93m | 12:03PM0.47m | 00:13AM0.94m | 1:28AM0.95m | 2:47AM0.98m | 3:51AM1.03m | 6:41PM0.54m | 4:42AM1.09m | ||||||||||
Low Tide | 3:48PM0.38m | 5:35AM0.39m | 3:49PM0.42m | 7:25AM0.40m | 3:28PM0.44m | 9:52AM0.36m | 11:01AM0.29m | 11:37AM0.24m | 12:05PM0.19m | 9:07PM0.52m | |||||||||||
 | |  |  |  |  | |  | | | | | | | | | | | | | | |
 | 5:35 | — | — | 5:35 | — | — | 5:35 | — | — | 5:35 | — | — | 5:35 | — | — | 5:37 | — | — | 5:37 | — | — |
 | — | 6:24 | — | — | 6:24 | — | — | 6:23 | — | — | 6:22 | — | — | 6:22 | — | — | 6:21 | — | — | 6:21 | — |
mm | 2 | 3 | — | — | — | 15 | 16 | 8 | 16 | 8 | 6 | 13 | 5 | 2 | 7 | 1 | — | 10 | 4 | 3 | 2 |
Temp °C | 30 | 29 | 28 | 29 | 30 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 29 | 29 | 28 | 29 | 29 | 29 |
Feels °C | 29 | 29 | 28 | 30 | 32 | 31 | 29 | 29 | 29 | 29 | 28 | 29 | 29 | 29 | 32 | 31 | 31 | 32 | 34 | 33 | 32 |
Swell 1 Height (m) Direction Period (s) | SW 8 | SSW 8 | SSW 9 | SSW 8 | SSW 8 | ENE 9 | ENE 8 | ENE 8 | ENE 9 | ENE 8 | ENE 9 | ENE 9 | WSW 11 | — | ESE 10 | ESE 10 | SW 9 | ESE 7 | SW 9 | SW 8 | SW 9 |
| kJ | 196 | 202 | 280 | 222 | 188 | 61 | 50 | 37 | 30 | 14 | 7 | 7 | 170 | — | 19 | 18 | 911 | 9 | 695 | 534 | 563 |
Swell 2 Height (m) Direction Period (s) | ESE 10 | ESE 10 | ESE 10 | ESE 10 | SSW 11 | SE 8 | SE 9 | SE 9 | — | — | — | — | ESE 10 | — | NE 9 | E 9 | ESE 10 | ESE 9 | E 16 | E 15 | E 13 |
| kJ | 11 | 10 | 10 | 10 | 48 | 15 | 13 | 13 | — | — | — | — | 10 | — | 3 | 2 | 18 | 17 | 80 | 157 | 229 |
Swell 3 Height (m) Direction Period (s) | SE 7 | ESE 10 | SE 8 | SSE 8 | ENE 9 | E 10 | — | — | — | — | — | — | ENE 8 | — | — | — | E 16 | E 18 | ESE 9 | E 19 | E 19 |
| kJ | 2 | 10 | 2 | 6 | 35 | 2 | — | — | — | — | — | — | 7 | — | — | — | 5 | 24 | 8 | 63 | 252 |
Wind waves Height (m) Direction Period (s) | ENE 5 | ENE 10 | ENE 6 | ENE 6 | ENE 6 | SSW 10 | SSW 9 | SSW 9 | SSW 10 | SW 10 | SW 10 | SW 10 | SW 10 | SW 11 | SW 10 | SW 9 | — | SW 9 | — | — | — |
| kJ | 74 | 208 | 190 | 97 | 40 | 838 | 948 | 1158 | 2420 | 2721 | 2629 | 2382 | 2074 | 2434 | 1790 | 1119 | — | 931 | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 859 | 859 | 316 | 79 | 1160 | 14 | 316 | 148 | 148 | 316 | 363 | 348 | 1464 | 42 | 14 | 42 | 14 | 2 | 0 | 0 | 0 |
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.
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