Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 19 Aug 2026:
- Best quality surf: Friday 21 Aug, 11PM (local time) - 5ft (1.6m), 10s period, NW swell with glassy winds.
- Most powerful swell: Friday 21 Aug, 11AM (local time) - 6ft (1.8m), 10s period, NW swell with 634 kJ wave energy.
- Next surfable swell (1★+): Friday 21 Aug, 11PM (local time) - 5ft (1.6m), 10s 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 Friday (Aug 21) at 11PM. The primary swell is predicted to be 1.6m and 10s 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 1.8m 10s and forecast to arrive on Friday (Aug 21) at 11AM. Winds are predicted to be onshore at the time the swell arrives.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 11PM (Fri 21st Aug) | 5ft (1.6m) 10s |
| Best Surf | 11PM (Fri 21st Aug) | 5ft (1.6m) 10s |
| Most Powerful | 11AM (Fri 21st Aug) | 6ft (1.8m) 10s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright, let’s get into it. The surf’s been a bit of a tease this week, but there’s some real potential lurking out there in the extended window if you’re patient.
Right now, we’ve got a flat spell. The coming days are pretty grim for any real waves, with just small, weak pulses that aren't worth getting wet for. The energy is low and the wind’s mostly on it, so it’s a good time to sort your gear or wax a new board. This flatness hangs around for the first few days, a real bummer.
Then things start to get interesting. On the 20th, we see the first real push of swell, but it’s still on the small side and the wind is messy. By Friday the 21st, the swell is up to 6ft but the wind is all over it. It’s more of a grindy, onshore mess than a clean option. You can feel the ocean stirring, but it’s not ready yet.
The standout window is shaping up for Saturday the 22nd. The swell drops a touch to 4ft but the wind goes light and glassy in the morning. That’s the kind of clean, rippable condition we all crave. The energy is moderate (241) and it’s all coming from the northwest, which is right in the wheelhouse for Guethary - Les Alcyons/Avalanche (Aquitaine). It’s an expert reef, so it’s not one for the faint of heart, and it can get crowded, so get out there early. This is the time to charge.
After that, the surf fades back down into the weekend, with small, poor waves and no real energy behind them. The start of the next week looks like another flat spell.
The good news is that the long-range charts are showing another pulse. Towards the 1st and 2nd of September, we’ve got promising signs. The swell is back up to the 4-5ft range, the direction is still a favorable WNW/NW, and the wind is looking a lot cleaner. The 2nd looks particularly good with a morning of glassy conditions and a solid 5ft of swell (360 energy). It's a while away, so forecasts can change, but it’s got the makings of a good one. The morning of the 1st also looks clean with 4ft.
For the second week, just keep an eye on that period around the 1st and 2nd of September. It’s the most promising of the bunch, but with it being that far out, treat it as a promising idea rather than a sure thing.
Rusty.
Short Range ForecastLight rain (total 8mm), mostly falling on Thu night. Warm (max 23°C on Wed afternoon, min 18°C on Wed morning). Wind will be generally light. | Days 5-7 Weather SummaryHeavy rain (total 30mm), heaviest during Mon afternoon. Warm (max 21°C on Fri night, min 16°C on Sat night). Wind will be generally light. | ||||||||||||||||||
Wednesday 19 | Thursday 20 | Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | ||||||||||||||
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 7 | NW 6 | WNW 8 | NW 13 | NW 11 | NW 11 | NW 10 | NW 10 | NW 10 | NW 10 | NW 9 | NW 9 | NW 8 | NW 8 | NW 7 | NW 7 | NW 7 | NNW 6 | NW 6 |
Wave Graph  | |||||||||||||||||||
 kJ | 13 | 9 | 6 | 83 | 304 | 399 | 392 | 634 | 569 | 425 | 241 | 225 | 173 | 96 | 75 | 60 | 36 | 27 | 43 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | on | cross-on | cross-on | cross-on | cross-on | on | on | glassy | glassy | cross-off | cross-off | cross-off | cross-on | cross-off | glassy | glassy | cross-on |
High Tide | 9:13PM3.21m | 9:33AM3.04m | 9:57PM2.89m | 10:21AM2.81m | 10:56PM2.63m | 11:31AM2.63m | 00:26AM2.48m | 1:09PM2.59m | 2:03AM2.54m | 2:31PM2.73m | 3:07AM2.71m | 3:24PM2.96m | 3:51AM2.93m | ||||||
Low Tide | 3:21AM0.82m | 3:43PM0.94m | 4:07AM1.12m | 4:39PM1.21m | 5:08AM1.36m | 5:56PM1.38m | 6:31AM1.47m | 7:27PM1.38m | 7:56AM1.39m | 8:39PM1.22m | 8:57AM1.19m | 9:30PM0.99m | |||||||
 | | |  |  | |  |  | |  | |  |  |  |  | | | |  | |
 | — | 7:15 | — | — | 7:16 | — | — | 7:16 | — | — | 7:18 | — | — | 7:18 | — | — | 7:20 | — | — |
 | 9:06 | — | — | 9:04 | — | — | 9:01 | — | — | 9:00 | — | 8:59 | — | — | 8:58 | — | — | 8:55 | — |
mm | — | — | — | — | — | — | 3 | 3 | 2 | — | 1 | — | 9 | 8 | 1 | — | 4 | 7 | 6 |
Temp °C | 22 | 21 | 23 | 22 | 22 | 22 | 20 | 20 | 21 | 21 | 19 | 19 | 18 | 16 | 18 | 18 | 16 | 17 | 19 |
Feels °C | 23 | 23 | 24 | 23 | 24 | 22 | 20 | 20 | 20 | 20 | 20 | 18 | 18 | 15 | 18 | 18 | 16 | 18 | 18 |
Swell 1 Height (m) Direction Period (s) | NW 7 | NW 6 | NNW 6 | NW 13 | NW 11 | NW 11 | NW 10 | NW 10 | NW 10 | NW 10 | NW 9 | NW 9 | NW 8 | NW 8 | NW 7 | NW 7 | NW 7 | NNW 6 | NW 6 |
| kJ | 13 | 9 | 3 | 83 | 304 | 399 | 392 | 634 | 569 | 425 | 241 | 225 | 173 | 96 | 75 | 60 | 36 | 27 | 43 |
Swell 2 Height (m) Direction Period (s) | NNW 5 | WNW 8 | WNW 8 | NW 7 | — | — | — | — | — | — | — | — | — | — | W 8 | — | — | W 8 | W 10 |
| kJ | 5 | 6 | 6 | 12 | — | — | — | — | — | — | — | — | — | — | 1 | — | — | 1 | 2 |
Swell 3 Height (m) Direction Period (s) | WNW 8 | — | NW 11 | WNW 7 | — | — | — | — | — | — | — | — | — | — | — | — | — | W 10 | — |
| kJ | 7 | — | 5 | 5 | — | — | — | — | — | — | — | — | — | — | — | — | — | 2 | — |
Wind waves Height (m) Direction Period (s) | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
| kJ | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 526 | 490 | 597 | 53 | 6 | 147 | 12 | 12 | 12 | 0 | 0 | 0 | 0 | 1 | 6 | 1 | 21 | 56 | 279 |
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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