Surf Forecasts:
Nai Harn Beach surf forecast from 18 Aug 2026:
- Most powerful swell: Thursday 20 Aug, 10AM (local time) - 6.5ft (2.0m), 7s period, W swell with 422 kJ wave energy.
Best Forecast Surf Conditions for Nai Harn Beach this week:
The most powerful waves expected at Nai Harn Beach in the next 16 days are 2.0m 7s and forecast to arrive on Thursday (Aug 20) at 10AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 1.9m 8s period and expected on Tuesday (Aug 25) at 7AM.
| Wave Type | Time (+07) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 10AM (Thu 20th Aug) | 6.5ft (2.0m) 7s |
Table - best surf conditions forecast for Nai Harn Beach over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s be straight with you – the outlook for Nai Harn Beach is a tough one. We’ve got a solid 16-day window ahead, but honestly, for the paddler, it’s looking pretty grim. The wind is just not playing ball at all.
We kick off on Tuesday, the 18th of August, with a tiny little 3ft swell out of the West, but it’s got a short period of 8 seconds and the wind is a messy cross-on at 12 mph. The water temp is sitting at a warm 86°F which is about normal for the time of year, so you won’t need a wetsuit, but you’ll be fighting the chop. The wave energy is moderate (131), but the conditions are just poor.
The rest of the week doesn’t get any better. Through Wednesday the 19th, the swell bumps up to 4ft, but that cross-on wind picks up to 19 mph, making it lumpy. By Thursday the 20th, we see a bit of size – 7ft from the West with a short period of 7 seconds – but the wind is a fresh 22 mph cross-on. The combined energy is strong (422), but it’s a complete mess. This is more of a kite-surfing setup than a paddle session.
There’s a brief moment on Friday the 21st where the wind goes “on” (offshore), but it’s still 19 mph and the swell is 6ft with a poor period. The water is still a mess. Honestly, it’s not worth the paddle out.
We then hit a long, flat spell. From Saturday the 22nd right through to the 26th of August, the swell drops to a measly 0.3ft to 0.7ft, and the wind stays cross-on. That’s nearly a week of nothing.
The only real event in the window is around the 27th of August. The swell kicks back up to 7ft from the West, with a period of 8 seconds. The combined energy is strong (527), but again, the wind is a cross-on 19 mph. That’s a lot of power, but it’s going to be a choppy, blown-out wall. This size is getting into expert-only territory, and even then, it won’t be pretty.
The end of the month and into September sees more of the same: 8ft on the 29th and 30th, but always with that cross-on wind. The period is still short, so the waves will be crumbly and hard to ride. The combined energy hits 817 on the 29th, which is very strong, but it’s almost all windswell.
The very last day, 2nd of September, shows a brief drop to 3ft from the West with a gentler breeze of 9 mph, but it’s still cross-on and the period is 8 seconds. It’s a slight improvement, but nothing to get excited about.
If you’re desperate for a paddle, the best of a bad bunch is the swell on the 27th and 28th of August – it’s the biggest, but you’ll be fighting the wind. For pure, clean surf, we don’t really have a standout. The rest of the time, the beach is better suited for a swim than a surf.
Hang in there, the trade winds have to ease off sometime.
Rusty.
Short Range ForecastLight rain (total 6mm), mostly falling on Thu afternoon. Warm (max 29°C on Tue morning, min 28°C on Tue morning). Mainly fresh winds. | Days 4-6 Weather SummaryModerate rain (total 18mm), heaviest on Sun afternoon. Warm (max 29°C on Sat afternoon, min 28°C on Fri morning). Mainly fresh winds. | ||||||||||||||||||||
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) | W 8 | WSW 21 | W 6 | W 6 | WSW 20 | WSW 19 | W 7 | W 8 | WSW 18 | W 7 | W 8 | W 7 | W 7 | WSW 16 | W 8 | WSW 15 | SW 15 | W 15 | W 19 | W 15 | W 18 |
Wave Graph | |||||||||||||||||||||
113 | 45 | 69 | 96 | 75 | 72 | 422 | 399 | 60 | 348 | 282 | 177 | 86 | 25 | 84 | 23 | 9 | 4 | 7 | 4 | 6 | |
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-on | cross-on | cross-on | cross-on | cross-on | on | on | cross-on | cross-on | on | on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on |
High Tide | 1:36PM1.58m | 2:04AM1.62m | 2:05PM1.41m | 2:39AM1.50m | 2:39PM1.24m | 3:28AM1.38m | 3:34PM1.08m | 5:01AM1.28m | 6:22PM1.00m | 7:14AM1.32m | 8:21PM1.11m | 8:24AM1.46m | 9:05PM1.26m | ||||||||
Low Tide | 7:44PM0.32m | 8:14AM0.52m | 8:12PM0.47m | 8:56AM0.66m | 8:43PM0.62m | 10:04AM0.80m | 9:36PM0.76m | 12:39PM0.83m | 11:56PM0.83m | 2:24PM0.71m | 1:51AM0.75m | 3:07PM0.55m | 2:46AM0.60m | ||||||||
6:18 | — | — | 6:18 | — | — | 6:18 | — | — | 6:18 | — | — | 6:18 | — | — | 6:18 | — | — | 6:18 | — | — | |
— | 6:40 | — | — | 6:40 | — | — | 6:39 | — | — | 6:39 | — | — | 6:38 | — | — | 6:38 | — | — | 6:37 | — | |
mm | 1 | — | — | — | — | — | 2 | 3 | — | 1 | — | — | 2 | — | 2 | 2 | 6 | 5 | 5 | 2 | 8 |
Temp °C | 29 | 29 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 29 | 28 | 28 | 28 | 28 | 28 | 28 | 28 |
Feels °C | 30 | 30 | 29 | 27 | 27 | 28 | 27 | 27 | 29 | 28 | 29 | 31 | 30 | 30 | 30 | 29 | 29 | 28 | 28 | 29 | 28 |
Swell 1 Height (m) Direction Period (s) | SW 14 | WSW 21 | W 8 | WSW 20 | WSW 20 | WSW 19 | — | WSW 18 | WSW 18 | WSW 17 | W 8 | WSW 16 | W 7 | W 8 | W 8 | WSW 15 | SW 15 | W 15 | W 15 | W 15 | W 18 |
8 | 45 | 12 | 77 | 75 | 72 | — | 62 | 60 | 57 | 282 | 26 | 206 | 223 | 219 | 23 | 9 | 4 | 4 | 4 | 6 | |
Swell 2 Height (m) Direction Period (s) | W 23 | W 8 | WSW 22 | SW 13 | W 13 | — | — | — | — | — | WSW 17 | WSW 16 | WSW 16 | WSW 16 | WSW 16 | — | — | — | W 19 | — | W 14 |
10 | 1 | 45 | 7 | 3 | — | — | — | — | — | 54 | 26 | 25 | 25 | 24 | — | — | — | 7 | — | 4 | |
Swell 3 Height (m) Direction Period (s) | — | SW 14 | W 13 | W 16 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
— | 8 | 4 | 5 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | |
Wind waves Height (m) Direction Period (s) | W 8 | W 7 | W 6 | W 6 | W 6 | W 7 | W 7 | W 8 | W 8 | W 7 | W 8 | W 7 | W 7 | — | W 8 | W 8 | W 7 | W 7 | W 7 | W 7 | W 8 |
113 | 89 | 69 | 96 | 182 | 233 | 422 | 399 | 291 | 348 | 118 | 177 | 86 | — | 84 | 245 | 236 | 233 | 287 | 303 | 320 | |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 4 | 4 | 4 | 635 | 636 | 635 | 635 | 635 | 24 | 635 | 24 | 4 | 4 | 24 | 24 | 4 | 4 | 24 | 24 | 24 | 4 |
Best forecast wave conditions in Phuket | |||||||||||||||||||||
Best forecast wave conditions in Thailand | |||||||||||||||||||||
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Information about the Nai Harn Beach Surf forecast
The above surf forecast table for Nai Harn Beach provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Nai Harn Beach can be found by selecting the local surf guide option on the grey menu. Our Nai Harn Beach 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 (Nai Harn Beach) 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 Nai Harn Beach 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.
Nai Harn Beach is 8 km (5 miles) from the city of Ban Chalong. If you plan a holiday in Phuket, look for hotels and other accommodation in Ban Chalong. Ban Chalong has rooms for a wide range of budgets as well as car hire and transport links.











