Guethary - Les Alcyons/Avalanche Surf Break

Lat Long: 43.43° N 1.62° W

Guethary - Les Alcyons/Avalanche Surf Forecast and Surf Report

Issued: 7 pm 08 Aug 2026 (local time)

Forecast update in  hr  min

Today's Guethary - Les Alcyons/Avalanche sea temperature is
24.5° C
2.8° 

Guethary - Les Alcyons/Avalanche surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.


Guethary - Les Alcyons/Avalanche surf forecast from 8 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, 5AM (local time) - 2.5ft (0.8m), 11s period, WNW swell with 130 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 5AM. Winds are predicted to be cross-onshore at the time the swell arrives.

Wave TypeTime (CEST) & Date Wave Height & Period
Next good surf (1 star+)11PM (Mon 10th Aug)2.5ft (0.8m) 10s
Best Surf11PM (Mon 10th Aug)2.5ft (0.8m) 10s
Most Powerful 5AM (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, Rusty here, let's look at what's cookin' for the Guethary area.

Honestly, I gotta be straight with you – the next couple of weeks look pretty bleak for the experts-only reef at Guethary - Les Alcyons/Avalanche. We're looking at a proper flat spell to kick things off. The water is sitting at 76° right now, which is way warmer than usual for this time of year, almost 5° above normal, so that's a bit of a weird one.

From the 8th of August all the way through until the 22nd, it's a long, dry stretch of nothing. Tiny waves, cross-shore breezes, and the combined wave energy is mostly weak, barely cracking 100 (14) on the 8th, and only occasionally getting into a moderate range of 120 or so. It's mostly poor conditions, not worth paddling out for.

We finally see a change on the 23rd of August. The swell starts to build, and by Sunday afternoon, we're looking at a solid 8ft of WNW swell on the face. The period jumps to 11 seconds, which gives it some real grunt, and the combined energy rockets up to 1410 – that's a strong pulse of energy. The wind is onshore, but with that much power, this spot will be holding a lot of water. At 8ft, this is strictly for experts only; it's gonna be a heavy, powerful wave. The morning of the 23rd is a bit smaller, around 6ft, but with the same onshore wind. It's not perfect, but it's the only real chance for a wave in the whole outlook.

The 22nd of August morning has a moment of glassy conditions with a small 3ft groundswell, but the energy is weak (96). It's a tease, but it won't have the push to make this reef work.

So, to be honest, the standout is the afternoon of the 23rd of August. It's the only day with any real size and power. Everything else is a write-off. You'll be waiting a long time for that one window.

Keep your eyes on the charts, but for now, it's a waiting game.

Rusty.

Short Range Forecast

Heavy rain (total 46mm), heaviest during Sat night. Warm (max 25°C on Tue afternoon, min 19°C on Tue morning). Wind will be generally light.

Days 5-7 Weather Summary

Mostly 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
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
0.3
NW
12
0.6
NW
10
0.8
NW
10
0.7
NW
10
0.7
NW
9
0.7
NW
9
0.8
NW
9
0.6
NW
9
0.6
NW
9
0.6
NW
8
0.6
NW
8
0.4
WNW
10
0.3
WNW
9
0.4
WNW
10
0.4
WNW
10
0.6
WNW
11
0.8
WNW
10
0.7
WNW
10
0.5
WNW
9
Wave Graph
Metric surfscale
Energy kJ
22
89
117
90
81
81
99
62
59
55
44
34
16
32
31
95
114
85
46
Wind (km/h)
15
SSE
15
W
10
WNW
5
W
10
NW
10
NW
5
W
5
N
10
NNW
5
SW
5
NNE
10
NNW
15
WSW
10
WNW
15
WNW
15
WSW
10
W
10
NW
10
W
Wind State
off
cross-on
cross-on
cross-on
on
on
glassy
cross-on
on
cross
glassy
on
cross
cross-on
on
cross-on
cross-on
on
cross-on
High Tide
1:51AM2.98m
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
Low Tide
7:56AM0.96m
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
rain showers
part cloud
part cloud
thunderstorm
part cloud
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
clear
part cloud
clear
clear
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
7:03
7:05
7:05
7:07
7:07
7:09
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
9:20
9:19
9:16
9:15
9:14
9:13
9:12
 mm
40
6
Temp °C
23
24
23
22
22
23
23
22
25
23
24
27
25
23
25
23
21
23
22
Feels °C
23
25
23
23
24
24
24
24
27
26
28
29
28
25
27
25
22
25
23
  • Map Icons:
  • Break
  • Live Wave Height (m)
  • Live Wind Speed (km/h)
  • Surf Rating (10 Max)
  • Ocean Swells (m)
  • Wind Speed (km/h)
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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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