Surf Forecasts:
Guethary - Les Alcyons/Avalanche surf forecast from 18 Jul 2026:
- Best quality surf: Tuesday 21 Jul, 8AM (local time) - 3.5ft (1.1m), 7s period, NNW swell with cross-offshore winds.
- Most powerful swell: Tuesday 21 Jul, 2AM (local time) - 4ft (1.2m), 7s period, NNW swell with 139 kJ wave energy.
- Next surfable swell (1★+): Tuesday 21 Jul, 8AM (local time) - 3.5ft (1.1m), 7s period with NNW 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 Tuesday (Jul 21) at 8AM. The primary swell is predicted to be 1.1m and 7s period with a secondary swell of 0.2m and 11s. The wind is predicted to be cross-offshore as the swell arrives.
The most powerful waves expected at Guethary - Les Alcyons/Avalanche in the next 16 days are 1.2m 7s and forecast to arrive on Tuesday (Jul 21) at 2AM. 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+) | 8AM (Tue 21st Jul) | 3.5ft (1.1m) 7s |
| Best Surf | 8AM (Tue 21st Jul) | 3.5ft (1.1m) 7s |
| Most Powerful | 2AM (Tue 21st Jul) | 4ft (1.2m) 7s |
Table - best surf conditions forecast for Guethary - Les Alcyons/Avalanche over the next 16 days.
The Lowdown
Alright folks, Rusty here. Let’s have a look at what’s coming down the line for Guethary - Les Alcyons/Avalanche.
Right off the bat, I gotta be straight with you – the next week and a half is looking pretty flat. We’re staring down a long stretch of tiny, weak waves. From now through July 27th, it’s all undersized and messed up by the wind. There’s a few mornings where it’s glassy, but the swell is just too small – we’re talking 0.7ft to 3ft with short-period stuff that’s got no push. The wave energy is mostly in the double digits (11 to 306), which tells you there’s nothing to get excited about. You’d be better off taking the dog for a walk.
Then, on the 28th of July, things start to stir. The swell is still marginal, but the wave energy jumps to 402 (moderate), and the period stretches to 9 seconds. Still, the wind is onshore, so it’s not a goer for any of us.
Now, here’s the light at the end of the tunnel. Wednesday the 29th of July is the standout. We’ve got a solid 5ft of swell rolling in from the NW with a handsome 11-second period – that’s proper groundswell with some grunt to it. The wave energy is a strong 595 (strong). The real kicker is the wind: glassy in the morning. This is a reef break that demands respect, and with that long period, it’ll be lining up nicely. At 5ft, it’s getting into the expert zone, so this is for the crew who know what they’re doing. It could get a bit competitive out there, as crowds are likely.
After that, the swell backs off quickly. The 30th sees a drop to 4ft, and the wind goes cross-onshore, so it’s back to mediocrity.
So, to wrap it up: you’ve got a long wait for one good morning. Mark your calendar for the 29th of July, set the alarm, and be on it early. The water temp is about average for this time of year, nothing wild to report there.
Rusty.
Short Range ForecastMostly dry. Warm (max 24°C on Sun afternoon, min 19°C on Sat night). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 25°C on Tue afternoon, min 19°C on Tue morning). Wind will be generally light. | ||||||||||||||||||||
Saturday 18 | Sunday 19 | Monday 20 | Tuesday 21 | Wednesday 22 | Thursday 23 | Friday 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) | NW 4 | WNW 8 | WNW 9 | NNW 10 | NW 9 | NNW 6 | NNW 7 | NNW 7 | NNW 7 | NNW 7 | NNW 7 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | N 5 |
Wave Graph  | |||||||||||||||||||||
 kJ | 7 | 7 | 8 | 10 | 20 | 96 | 79 | 102 | 139 | 93 | 73 | 104 | 35 | 36 | 58 | 42 | 35 | 41 | 25 | 31 | 11 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | glassy | on | cross | cross-on | on | cross | cross-on | on | cross | glassy | on | cross | cross-on | on | cross | cross-on | on | cross | cross | cross-on | cross |
High Tide | 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 | 1:48PM2.75m | 2:26AM2.70m | |||||||
Low Tide | 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 | 7:14AM1.27m | 7:55PM1.23m | ||||||||
 | |  | |  |  | | | | | | | | | | | | | | | | |
 | 6:41 | — | — | 6:41 | — | — | 6:43 | — | — | 6:43 | — | — | 6:45 | — | — | 6:46 | — | — | 6:47 | — | — |
 | — | — | 9:43 | — | — | 9:42 | — | — | 9:40 | — | — | 9:39 | — | — | 9:38 | — | — | 9:38 | — | — | 9:37 |
mm | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 22 | 23 | 22 | 22 | 24 | 23 | 23 | 24 | 23 | 22 | 25 | 23 | 23 | 25 | 23 | 22 | 23 | 23 | 25 | 28 | 25 |
Feels °C | 24 | 23 | 23 | 23 | 25 | 24 | 23 | 24 | 21 | 23 | 23 | 21 | 23 | 24 | 22 | 22 | 23 | 24 | 24 | 25 | 25 |
Swell 1 Height (m) Direction Period (s) | NW 4 | WNW 8 | NNW 4 | NNW 4 | NNW 5 | NNW 6 | NNW 7 | NNW 7 | NNW 7 | NNW 7 | NNW 7 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NNW 6 | NW 9 | N 5 |
| kJ | 4 | 7 | 5 | 7 | 7 | 96 | 79 | 102 | 139 | 93 | 73 | 104 | 35 | 36 | 58 | 42 | 35 | 41 | 25 | 3 | 11 |
Swell 2 Height (m) Direction Period (s) | WNW 8 | — | WNW 9 | WNW 8 | NW 9 | — | NW 8 | NW 13 | NW 12 | WNW 11 | WNW 11 | WNW 10 | WNW 10 | WNW 10 | WNW 10 | N 6 | WNW 9 | WNW 9 | NW 9 | — | NNW 6 |
| kJ | 7 | — | 8 | 7 | 20 | — | 17 | 6 | 6 | 12 | 11 | 10 | 10 | 10 | 9 | 10 | 8 | 8 | 3 | — | 3 |
Swell 3 Height (m) Direction Period (s) | — | — | NW 11 | NNW 10 | — | — | NW 13 | — | — | — | — | — | — | — | — | WNW 10 | — | — | — | — | W 8 |
| kJ | — | — | 4 | 10 | — | — | 7 | — | — | — | — | — | — | — | — | 9 | — | — | — | — | 1 |
Wind waves Height (m) Direction Period (s) | — | NNW 4 | — | — | — | — | — | — | WSW 3 | — | — | — | — | — | — | — | — | — | — | NNW 6 | — |
| kJ | — | 3 | — | — | — | — | — | — | 3 | — | — | — | — | — | — | — | — | — | — | 31 | — |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 1168 | 1168 | 711 | 578 | 465 | 17 | 28 | 87 | 12 | 0 | 87 | 13 | 7 | 87 | 17 | 91 | 197 | 31 | 313 | 887 | 453 |
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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