Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 9 Aug 2026:
- Best quality surf: Monday 10 Aug, 11PM (local time) - 2.5ft (0.8m), 10s period, NW swell with glassy winds.
- Most powerful swell: Friday 14 Aug, 2AM (local time) - 2.5ft (0.8m), 11s period, WNW swell with 138 kJ wave energy.
- Next surfable swell (1★+): Monday 10 Aug, 11PM (local time) - 2.5ft (0.8m), 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 Monday (Aug 10) at 11PM. The primary swell is predicted to be 0.8m 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 0.8m 11s and forecast to arrive on Friday (Aug 14) at 2AM. Winds are predicted to be cross-onshore at the time the swell arrives.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 11PM (Mon 10th Aug) | 2.5ft (0.8m) 10s |
| Best Surf | 11PM (Mon 10th Aug) | 2.5ft (0.8m) 10s |
| Most Powerful | 2AM (Fri 14th Aug) | 2.5ft (0.8m) 11s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright, this is Rusty, and I’m looking at a long, tough stretch ahead for this spot.
We’re talking about Guethary - Les Alcyons/Avalanche, a reef break that usually knows how to handle itself, but it’s going quiet for a long time. From Sunday the 9th all the way through to the following Saturday, there’s nothing doing. The swell numbers are tiny, mostly around 2 to 3ft, the energy is weak (all under 100), and the wind is blowing cross-onshore or onshore, messing up any chance of clean waves. The water is running much warmer than usual for this time of year at 76°, which feels a bit off, but it doesn't help the surf.
There’s a big, empty gap here. You could easily take a week off and not miss a thing.
We get a small pulse on Tuesday the 18th in the afternoon, with a 5ft wave out of the NW but with a lousy 6-second period. The energy bumps up to 200, but it’s a short-period, weak swell, and the wind is still onshore. It’s only a 1 out of 10, and that size is for experienced heads only.
The one tiny window I’d even consider is Thursday the 20th in the morning. The wind goes glassy, dead calm, and the swell is a clean 2ft from the NW with a 12-second period. That’s proper groundswell energy for a reef – it’ll wrap in with some punch. The energy reading of 169 is solid for such a small wave. But again, the overall rating is only a 1 out of 10, and the afternoon gets messy straight away. So if a glassy, 2-3ft wave sounds good, that’s your best shot. The rest of the second week is more of the same: poor, choppy, onshore slop.
Honestly, for standing up on a surfboard, this forecast is a downer. If you’re into kite surfing, the stronger winds on the 22nd and some of those bigger but choppier days might be more interesting. For the rest of us, it’s time to find something else to do.
Rusty.
Short Range ForecastLight rain (total 5mm), mostly falling on Sun night. Warm (max 25°C on Tue afternoon, min 19°C on Tue morning). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 27°C on Wed afternoon, min 20°C on Wed morning). Wind will be generally light. | ||||||||||||||||||||
Sunday 9 | Monday 10 | Tuesday 11 | Wednesday 12 | Thursday 13 | Friday 14 | Saturday 15 | |||||||||||||||
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 10 | NW 10 | NW 10 | NW 9 | NW 9 | NW 9 | NW 9 | NW 9 | NW 8 | NW 8 | WNW 10 | WNW 9 | WNW 10 | WNW 12 | WNW 11 | WNW 10 | WNW 10 | WNW 9 | WNW 9 | WNW 9 | WNW 5 |
Wave Graph  | |||||||||||||||||||||
 kJ | 89 | 117 | 90 | 81 | 81 | 81 | 62 | 59 | 69 | 44 | 34 | 28 | 31 | 58 | 138 | 114 | 85 | 73 | 54 | 43 | 56 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | cross | cross-on | on | glassy | glassy | on | cross | glassy | on | cross | cross-on | on | cross-on | on | on | cross-on | cross-on | on | cross-on |
High Tide | 2:25PM3.17m | 3:06AM3.18m | 3:31PM3.46m | 4:06AM3.43m | 4:25PM3.77m | 4:56AM3.64m | 5:13PM4.01m | 5:41AM3.78m | 5:57PM4.15m | 6:23AM3.83m | 6:38PM4.16m | 7:02AM3.79m | 7:18PM4.05m | ||||||||
Low Tide | 8:38PM0.72m | 9:04AM0.74m | 9:41PM0.43m | 10:01AM0.47m | 10:34PM0.15m | 10:50AM0.23m | 11:22PM-0.05m | 11:34AM0.07m | 00:05AM-0.14m | 12:16PM-0.01m | 00:46AM-0.12m | 12:56PM0.03m | 1:25AM0.01m | ||||||||
 |  |  | |  |  | | | | | | | | | | | | | | |  | |
 | 7:03 | — | — | 7:05 | — | — | 7:05 | — | — | 7:07 | — | — | 7:07 | — | — | 7:09 | — | — | 7:09 | — | — |
 | — | — | 9:19 | — | — | 9:16 | — | — | 9:15 | — | — | 9:14 | — | — | 9:13 | — | — | 9:12 | — | — | 9:09 |
mm | — | 1 | 4 | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | 3 |
Temp °C | 24 | 23 | 22 | 21 | 24 | 23 | 22 | 25 | 23 | 23 | 27 | 24 | 23 | 25 | 23 | 22 | 24 | 23 | 25 | 25 | 28 |
Feels °C | 25 | 24 | 23 | 23 | 25 | 24 | 24 | 27 | 25 | 26 | 29 | 27 | 26 | 27 | 25 | 24 | 26 | 25 | 27 | 26 | 30 |
Swell 1 Height (m) Direction Period (s) | NW 10 | NW 10 | NW 10 | NW 9 | NW 9 | NW 9 | NW 9 | NW 9 | NW 8 | NW 8 | NW 8 | WNW 9 | WNW 10 | WNW 10 | WNW 11 | WNW 10 | WNW 10 | WNW 9 | WNW 9 | WNW 9 | WNW 8 |
| kJ | 89 | 117 | 90 | 81 | 81 | 81 | 62 | 59 | 69 | 44 | 28 | 28 | 31 | 30 | 138 | 114 | 85 | 73 | 54 | 43 | 26 |
Swell 2 Height (m) Direction Period (s) | W 9 | W 9 | NW 4 | W 7 | NNW 4 | NNW 5 | NNW 5 | NNW 4 | WNW 10 | WNW 11 | WNW 10 | NW 8 | NNW 7 | WNW 12 | — | — | NW 4 | — | NNW 5 | — | — |
| kJ | 2 | 2 | 5 | 4 | 1 | 6 | 4 | 4 | 9 | 12 | 34 | 14 | 5 | 58 | — | — | 4 | — | 9 | — | — |
Swell 3 Height (m) Direction Period (s) | — | — | W 8 | — | — | — | W 11 | — | W 13 | — | — | — | NW 14 | NW 6 | NW 6 | — | N 4 | — | W 4 | — | — |
| kJ | — | — | 5 | — | — | — | 2 | — | 3 | — | — | — | 7 | 2 | 2 | — | 1 | — | 3 | — | — |
Wind waves Height (m) Direction Period (s) | NW 6 | W 3 | — | — | — | — | — | — | — | — | — | WSW 3 | NW 4 | NW 4 | WNW 3 | WNW 4 | — | NW 6 | — | NW 4 | WNW 5 |
| kJ | 5 | 1 | — | — | — | — | — | — | — | — | — | 1 | 7 | 5 | 3 | 5 | — | 28 | — | 13 | 56 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 91 | 196 | 13 | 20 | 87 | 1 | 1 | 87 | 2 | 1 | 197 | 31 | 31 | 87 | 12 | 114 | 87 | 13 | 10 | 87 | 35 |
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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