Surf Forecasts:
Nai Harn Beach surf forecast from 17 Aug 2026:
- Most powerful swell: Thursday 20 Aug, 10AM (local time) - 6ft (1.9m), 7s period, W swell with 378 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 1.9m 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 4AM.
| Wave Type | Time (+07) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 10AM (Thu 20th Aug) | 6ft (1.9m) 7s |
Table - best surf conditions forecast for Nai Harn Beach over the next 16 days.
The Lowdown
Alright, grab a coffee and listen up. Rusty here.
Honestly, it’s a tough stretch ahead for Nai Harn Beach. We’re looking at a long, bleak run with hardly anything to get excited about. The water is sitting at a warm 86°, which is about normal for this time of year, so at least it’ll be a nice swim.
For the next two weeks, we’ve got a massive gap of poor conditions. From Monday, August 17th right through to the end of the month, the wind is a constant problem – mostly a cross-onshore breeze, often a fresh 19 mph, making everything choppy and lumpy. The swell sticks around 3 ft to 4 ft for a while, but it’s short-period, weak windswell with combined energy readings that are moderate at best (212 at the start). It’s just messy. There’s a bit of a bump around Thursday, August 20th, with swell jumping to 7 ft, but that's still cross-on and rough, and that size with a short period is really just for experts or kite surfers. Honestly, with that constant onshore wind and a beach-and-reef setup being so exposed, it looks far more interesting for kite surfing than paddle surfing.
Things don’t really change until the very end of the forecast. We get a tiny window on Monday, September 1st. The morning shows a glassy 0.7 ft WSW windswell with a very long period of 19 seconds. The combined energy is weak (57), so it’s barely surfable, but at least it’s clean. That’s the only moment in the whole 16 days where the wind gives us a break. The afternoon picks up a messy 5 ft onshore again, so that’s it.
There is no standout here. The only true positive is that glassy morning on the 1st of September, but even then, the swell is tiny. This is one of those blank runs that’s more normal for the area when the monsoon sets in. Forecasts can change, but right now, I’d leave the board at home for a couple of weeks.
Stay patient,
Rusty
Short Range ForecastLight rain (total 9mm), mostly falling on Tue morning. Warm (max 29°C on Tue morning, min 28°C on Mon night). Mainly fresh winds. | Days 4-6 Weather SummaryLight rain (total 6mm), mostly falling on Fri afternoon. Warm (max 28°C on Thu night, min 28°C on Thu night). Winds decreasing (fresh winds from the W on Thu night, light winds from the WSW by Fri 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) | W 8 | WSW 21 | WSW 22 | W 6 | W 6 | WSW 19 | W 7 | W 8 | WSW 18 | W 7 | W 7 | W 7 | W 7 | WSW 16 | WSW 16 | WSW 15 | SW 15 | W 15 | W 7 | W 7 | W 18 |
Wave Graph  | |||||||||||||||||||||
 kJ | 113 | 45 | 45 | 130 | 175 | 72 | 378 | 358 | 60 | 349 | 276 | 210 | 210 | 25 | 24 | 23 | 9 | 4 | 0 | 0 | 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 | cross-on | on | cross-on | on | on | cross-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 | 7:38AM0.38m | 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 | 2 | — | 3 | — | — | — | 2 | 1 | — | — | 1 | — | 1 | — | 1 | 1 | 2 | 4 | 3 | 3 | 2 |
Temp °C | 29 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 | 28 |
Feels °C | 30 | 28 | 30 | 28 | 27 | 27 | 27 | 27 | 29 | 28 | 30 | 32 | 31 | 30 | 30 | 28 | 29 | 29 | 28 | 28 | 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 18 | WSW 17 | WSW 17 | WSW 16 | W 7 | W 8 | WSW 16 | WSW 15 | SW 15 | W 15 | — | — | W 18 |
| kJ | 8 | 45 | 12 | 77 | 75 | 72 | 64 | 106 | 60 | 29 | 54 | 26 | 210 | 187 | 24 | 23 | 9 | 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 | — | — | — | — | — | — | — |
| kJ | 10 | 1 | 45 | 7 | 3 | — | — | — | — | — | 27 | — | 25 | 25 | — | — | — | — | — | — | — |
Swell 3 Height (m) Direction Period (s) | — | SW 14 | W 13 | W 16 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | 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 7 | W 7 | — | — | W 8 | W 7 | W 7 | W 7 | W 7 | W 7 | W 8 |
| kJ | 113 | 86 | 60 | 130 | 175 | 233 | 378 | 358 | 299 | 349 | 276 | 210 | — | — | 164 | 206 | 254 | 203 | 274 | 340 | 362 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 4 | 4 | 4 | 4 | 635 | 636 | 636 | 635 | 635 | 24 | 635 | 24 | 4 | 635 | 4 | 4 | 24 | 4 | 24 | 24 | 24 |
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.
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