Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 17 Jul 2026:
- Most powerful swell: Tuesday 21 Jul, 2AM (local time) - 4.5ft (1.3m), 7s period, NNW swell with 145 kJ wave energy.
Best Forecast Surf Conditions for Guethary - Les Alcyons/Avalanche this week:
The most powerful waves expected at Guethary - Les Alcyons/Avalanche in the next 16 days are 1.3m 7s and forecast to arrive on Tuesday (Jul 21) at 2AM. Winds are predicted to be cross-shore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.3m 6s period and expected on Thursday (Jul 23) at 8AM.
| Wave Type | Time (CEST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 2AM (Tue 21st Jul) | 4.5ft (1.3m) 7s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright, grab a coffee and pull up a stool. Rusty here, and I’ve gotta be straight with you – for the next couple of weeks, the forecast for our local reef, Guethary - Les Alcyons/Avalanche, is a tough pill to swallow. The water is sitting at a balmy 77°, which is a whopping 8° warmer than normal for this time of year, so it feels like a bathtub, but that’s about the only upside.
We’re looking at a long, dry spell to kick things off. From Friday the 17th right through to the end of Sunday the 27th of July, it’s pretty much a write-off. The swell is tiny, the period is short, and the wind is mostly on it or cross-on. The energy is weak, with most combined energy readings sitting below 100 (27 to 71), which just isn’t enough to push any real shape into this reef. We’re talking ankle to knee-high slop at best, and it’s an expert-only spot when it’s working, so there’s nothing to get excited about. That’s almost two full weeks of flat spells.
The first real sign of life shows up on Monday the 28th of July. We get a bump in energy – the combined energy jumps to 499 in the morning and 409 in the afternoon – and the swell builds to 6 ft from the WNW with a period of 9 seconds. That’s a moderate wave energy (499) that’s finally got some push. The wind is a light cross-onshore, so it’s not perfect, but it’s rideable. The problem is the wave comment calls it “marginal” at best, and the score is still low. This is the only day that’s worth a look, but it’s a big “maybe”. The swell is just over 5 ft, so it’s getting into the territory where only the experienced crew should be out.
After that, it fades back into mediocrity. Wednesday the 30th of July has a bit of groundswell from the NW with a 12-second period, but the wind is on it, and the energy is still moderate at 408. It’s a long period, which means it’ll be lined up and better for the reef, but the wind will ruin it. The best chance for a clean session is on Friday the 31st of July, early morning, when the wind goes glassy. The swell is only 3 ft from the NW with a 10-second period, and the energy is low (119), but it’ll be clean. It’s a surfable wave, but very ordinary.
If you are a kitesurfer, the afternoon of Monday the 27th of July and Tuesday the 28th of July look better for you than for paddle surfing, with the cross-onshore winds and a bit of bump.
Don’t hold your breath on this one. It’s a classic summer lull for this spot.
Rusty.
Short Range ForecastMostly dry. Warm (max 24°C on Sun afternoon, min 19°C on Fri night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 25°C on Tue afternoon, min 19°C on Tue night). Wind will be generally light. | ||||||||||||||||||||
Friday 17 | Saturday 18 | Sunday 19 | Monday 20 | Tuesday 21 | Wednesday 22 | Thursday 23 | |||||||||||||||
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 5 | NW 5 | NNW 4 | NW 4 | WNW 8 | WNW 9 | NNW 10 | NW 9 | NNW 6 | NNW 6 | NNW 7 | NNW 7 | NNW 6 | NNW 6 | N 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 |
Wave Graph  | |||||||||||||||||||||
 kJ | 19 | 10 | 7 | 7 | 7 | 8 | 10 | 20 | 34 | 40 | 102 | 145 | 72 | 70 | 78 | 38 | 25 | 74 | 26 | 36 | 43 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | glassy | glassy | on | cross | cross-on | on | cross | on | on | cross | on | on | cross | cross | on | cross | cross | on | cross |
High Tide | 7:45PM4.02m | 8:13AM3.57m | 8:30PM3.83m | 8:57AM3.39m | 9:15PM3.56m | 9:43AM3.19m | 10:03PM3.26m | 10:31AM2.99m | 10:55PM2.98m | 11:27AM2.83m | 11:58PM2.77m | 12:35PM2.74m | 1:13AM2.67m | ||||||||
Low Tide | 1:21PM0.14m | 1:55AM0.06m | 2:06PM0.27m | 2:40AM0.26m | 2:52PM0.47m | 3:25AM0.51m | 3:40PM0.70m | 4:12AM0.78m | 4:32PM0.94m | 5:04AM1.02m | 5:33PM1.14m | 6:05AM1.20m | 6:43PM1.24m | ||||||||
 | |  |  | | | | | | | | | | | | | | | | | | |
 | 6:39 | — | — | 6:41 | — | — | 6:41 | — | — | 6:43 | — | — | 6:43 | — | — | 6:45 | — | — | 6:46 | — | — |
 | — | — | 9:44 | — | — | 9:43 | — | — | 9:42 | — | — | 9:40 | — | — | 9:39 | — | — | 9:38 | — | — | 9:38 |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 21 | 22 | 22 | 21 | 23 | 22 | 22 | 24 | 23 | 22 | 24 | 24 | 22 | 25 | 23 | 24 | 25 | 24 | 24 | 28 | 25 |
Feels °C | 23 | 23 | 23 | 23 | 23 | 23 | 23 | 24 | 24 | 23 | 25 | 24 | 23 | 23 | 21 | 23 | 23 | 23 | 24 | 27 | 25 |
Swell 1 Height (m) Direction Period (s) | WNW 9 | WNW 9 | NNW 4 | NW 4 | WNW 8 | NNW 4 | NNW 4 | NNW 5 | NNW 6 | NNW 6 | NNW 7 | NNW 7 | NNW 6 | NNW 6 | N 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 |
| kJ | 8 | 8 | 7 | 4 | 7 | 3 | 7 | 9 | 34 | 40 | 102 | 145 | 72 | 70 | 78 | 38 | 25 | 74 | 26 | 36 | 43 |
Swell 2 Height (m) Direction Period (s) | — | — | WNW 8 | WNW 8 | — | WNW 9 | WNW 8 | NW 9 | NW 8 | NW 8 | NW 12 | NW 12 | WNW 11 | WNW 11 | WNW 10 | WNW 10 | WNW 10 | WNW 10 | N 6 | WNW 9 | WNW 9 |
| kJ | — | — | 7 | 7 | — | 8 | 7 | 20 | 16 | 28 | 6 | 6 | 12 | 11 | 10 | 10 | 10 | 9 | 24 | 8 | 8 |
Swell 3 Height (m) Direction Period (s) | — | — | — | — | — | NW 11 | NNW 10 | — | — | W 13 | — | — | — | — | — | — | — | — | WNW 10 | — | — |
| kJ | — | — | — | — | — | 4 | 10 | — | — | 3 | — | — | — | — | — | — | — | — | 9 | — | — |
Wind waves Height (m) Direction Period (s) | NW 5 | NW 5 | — | — | NNW 4 | — | — | — | — | — | — | — | — | — | WSW 2 | — | — | — | — | — | — |
| kJ | 19 | 10 | — | — | 2 | — | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 765 | 2092 | 711 | 788 | 1289 | 619 | 465 | 197 | 17 | 17 | 87 | 12 | 20 | 87 | 17 | 7 | 197 | 17 | 6 | 197 | 17 |
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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