Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 2 Sep 2026:
- Best quality surf: Sunday 6 Sep, 2AM (local time) - 5ft (1.6m), 13s period, NW swell with cross-offshore winds.
- Most powerful swell: Saturday 5 Sep, 11PM (local time) - 5.5ft (1.7m), 13s period, NW swell with 911 kJ wave energy.
- Next surfable swell (1★+): Wednesday 2 Sep, 11AM (local time) - 3ft (0.9m), 8s period with NW swell.
Best Forecast Surf Conditions for Guethary - Les Alcyons/Avalanche this week:
The surf forecast for Guethary - Les Alcyons/Avalanche over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Wednesday (Sep 02) at 11AM. The primary swell is predicted to be 0.9m and 8s period. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Guethary - Les Alcyons/Avalanche in the next 16 days are 1.7m 13s and forecast to arrive on Saturday (Sep 05) at 11PM. Winds are predicted to be cross-shore at the time the swell arrives.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 11AM (Wed 2nd Sep) | 3ft (0.9m) 8s |
| Best Surf | 2AM (Sun 6th Sep) | 5ft (1.6m) 13s |
| Most Powerful | 11PM (Sat 5th Sep) | 5.5ft (1.7m) 13s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s get into it.
First up, we’ve got a bit of a slow start for the next few days. The surf is pretty small and weak, not really worth paddling out for. The water is sitting at 75°, which is 5° warmer than usual for this time of year – that’s a notable difference, so the water feels like a warm bath compared to normal.
The first real chance of a decent wave comes on the morning of Saturday the 5th. Guethary - Les Alcyons/Avalanche, an expert reef break, will see a clean 3 ft swell from the NW with a period of 9 seconds. The wind will be glassy, which is a major plus for clean conditions. The combined swell energy is moderate (226), so it’s not a powerhouse, but it’s a good start to the weekend.
But the standout session is Sunday morning, the 6th of September. This is the best on offer. The swell jumps to 5 ft from the NW, with a period of 12 seconds – that’s a solid groundswell with proper energy. The wind is offshore from the ESE at just 3 mph, so the face will be clean and lined up. Combined energy is strong (603). This is a true expert-level wave, and with the long period, it’s going to be a proper reef setup. Get on it early.
The rest of the week is a mixed bag. Monday the 7th is blown out with cross-onshore winds and messy conditions. The following days see small, marginal surf with onshore winds, nothing to get excited about. The morning of Saturday the 12th has a clean 3 ft from the WNW, but the wind is cross-on, so it’s only average.
Looking further out, the morning of Monday the 14th brings a glassy 4 ft from the NW with moderate energy (323), and the morning of Tuesday the 15th has a 5 ft swell from the NW with glassy conditions and moderate energy (283). Both are good options, but they’re a week and a half away, so keep an eye on the forecasts. The period is shorter (8 seconds), so expect a bit of a short-period bump rather than a long, drawn-out groundswell. The 5 ft is getting towards the top end for a reef, so only for the experienced crew.
Overall, you’ve got a couple of solid windows. The best bet is definitely Sunday morning, the 6th. Don’t sleep on it.
Rusty
Short Range ForecastMostly dry. Warm (max 26°C on Thu afternoon, min 16°C on Wed night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 32°C on Sun afternoon, min 18°C on Sat morning). Wind will be generally light. | ||||||||||||||||||||
Wednesday 2 | Thursday 3 | Friday 4 | Saturday 5 | Sunday 6 | Monday 7 | Tuesday 8 | |||||||||||||||
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) | NW 8 | NW 8 | NW 8 | NW 7 | NW 8 | NW 7 | WNW 8 | NW 8 | WNW 9 | NW 9 | NW 12 | NW 13 | NW 12 | NW 11 | NW 10 | NW 10 | WNW 14 | WNW 12 | WNW 11 | WNW 11 | NW 10 |
Wave Graph  | |||||||||||||||||||||
 kJ | 120 | 80 | 40 | 27 | 50 | 27 | 40 | 33 | 101 | 125 | 624 | 838 | 603 | 429 | 200 | 99 | 236 | 258 | 170 | 242 | 188 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | cross-on | glassy | cross-off | cross-on | cross-off | glassy | on | cross | glassy | cross-on | cross-off | off | on | cross-on | cross-on | cross-on | on | cross-on | on | on |
High Tide | 8:16AM3.47m | 8:38PM3.43m | 9:01AM3.28m | 9:30PM3.16m | 9:59AM3.06m | 10:42PM2.90m | 11:21AM2.90m | 00:20AM2.78m | 1:01PM2.94m | 1:56AM2.90m | 2:24PM3.19m | 3:05AM3.16m | 3:25PM3.51m | 3:58AM3.43m | |||||||
Low Tide | 2:24PM0.46m | 2:49AM0.60m | 3:13PM0.69m | 3:42AM0.87m | 4:17PM0.92m | 4:53AM1.11m | 5:44PM1.06m | 6:25AM1.19m | 7:21PM0.98m | 7:53AM1.03m | 8:38PM0.71m | 8:59AM0.75m | 9:35PM0.40m | ||||||||
 | |  | | | | | | | | |  | | | |  | | |  | | | |
 | 7:30 | — | — | 7:31 | — | — | 7:31 | — | — | 7:33 | — | — | 7:35 | — | — | 7:35 | — | — | 7:37 | — | — |
 | — | 8:40 | — | — | 8:38 | — | — | 8:37 | — | — | 8:35 | — | — | 8:34 | — | — | 8:31 | — | — | 8:30 | — |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 19 | 21 | 20 | 19 | 26 | 23 | 24 | 26 | 22 | 21 | 24 | 21 | 26 | 32 | 24 | 21 | 22 | 21 | 19 | 19 | 19 |
Feels °C | 20 | 21 | 20 | 19 | 25 | 23 | 23 | 25 | 22 | 23 | 24 | 23 | 27 | 31 | 25 | 21 | 22 | 23 | 21 | 19 | 20 |
Swell 1 Height (m) Direction Period (s) | NW 8 | NW 8 | NW 8 | NW 7 | NW 8 | NW 7 | WNW 8 | NW 8 | WNW 9 | NW 9 | NW 12 | NW 13 | NW 12 | NW 11 | NW 10 | NW 10 | WNW 5 | WNW 12 | WNW 11 | WNW 11 | NW 10 |
| kJ | 120 | 80 | 40 | 27 | 50 | 27 | 40 | 33 | 101 | 125 | 624 | 838 | 603 | 429 | 200 | 92 | 32 | 258 | 170 | 242 | 188 |
Swell 2 Height (m) Direction Period (s) | — | — | — | NW 10 | — | N 4 | NW 8 | WNW 8 | — | NW 13 | — | NNW 5 | — | — | W 19 | WNW 16 | WNW 14 | WNW 5 | NW 5 | — | NW 12 |
| kJ | — | — | — | 4 | — | 3 | 11 | 24 | — | 101 | — | 27 | — | — | 7 | 99 | 236 | 9 | 7 | — | 6 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | NW 9 | N 4 | — | — | — | — | — | — | — | — | — | NW 9 | NW 9 | — | — | — |
| kJ | — | — | — | — | — | 13 | 1 | — | — | — | — | — | — | — | — | — | 51 | 19 | — | — | — |
Wind waves Height (m) Direction Period (s) | — | — | — | — | N 3 | — | — | NNW 4 | WNW 4 | — | — | — | — | — | WNW 4 | WNW 6 | — | — | — | — | — |
| kJ | — | — | — | — | 1 | — | — | 1 | 4 | — | — | — | — | — | 9 | 47 | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 0 | 197 | 1 | 91 | 197 | 3 | 1 | 17 | 13 | 0 | 87 | 0 | 0 | 12 | 12 | 12 | 12 | 12 | 87 | 87 | 12 |
Best forecast wave conditions in La Cote Basque | |||||||||||||||||||||
Best forecast wave conditions in France | |||||||||||||||||||||
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Information about the Guethary - Les Alcyons/Avalanche Surf forecast
The above surf forecast table for Guethary - Les Alcyons/Avalanche provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Guethary - Les Alcyons/Avalanche can be found by selecting the local surf guide option on the grey menu. Our Guethary - Les Alcyons/Avalanche 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 (Guethary - Les Alcyons/Avalanche) 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 Guethary - Les Alcyons/Avalanche 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.
Guethary - Les Alcyons/Avalanche is 9 km (6 miles) from Biarritz. If you plan a holiday in La Cote Basque, look for hotels and other accommodation in Biarritz. Biarritz has rooms for a wide range of budgets as well as car hire and transport links.
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