Avellanas Rivermouth Surf Break

Lat Long: 10.24° N 85.84° W

Avellanas Rivermouth Surf Forecast and Surf Report

Issued: 5 am 28 Jul 2026 (local time)

Forecast update in  hr  min

Today's Avellanas Rivermouth sea temperature is
29.8° C
1.8° 

Avellanas Rivermouth surf forecast is for near shore open water. Breaking waves will often be smaller at less exposed spots.


Avellanas Rivermouth surf forecast from 28 Jul 2026:

  • Best quality surf: Tuesday 28 Jul, 12PM (local time) - 5.5ft (1.7m), 17s period, SW swell with cross-offshore winds.
  • Most powerful swell: Tuesday 28 Jul, 12PM (local time) - 5.5ft (1.7m), 17s period, SW swell with 1,722 kJ wave energy.
  • Next surfable swell (1★+): Tuesday 28 Jul, 12PM (local time) - 5.5ft (1.7m), 17s period with SW swell.

Best Forecast Surf Conditions for Avellanas Rivermouth this week:

The surf forecast for Avellanas Rivermouth over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Tuesday (Jul 28) at 12PM. The primary swell is predicted to be 1.7m and 17s period with a secondary swell of 0.4m and 9s. The wind is predicted to be cross-offshore as the swell arrives.

The most powerful waves expected at Avellanas Rivermouth in the next 16 days are 1.7m 17s and forecast to arrive on Tuesday (Jul 28) at 12PM. Winds are predicted to be cross-offshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.6m 4s period and expected on Saturday (Aug 01) at 6PM.

Wave TypeTime (CST) & Date Wave Height & Period
Next good surf (1 star+)12PM (Tue 28th Jul)5.5ft (1.7m) 17s
Best Surf12PM (Tue 28th Jul)5.5ft (1.7m) 17s
Most Powerful12PM (Tue 28th Jul)5.5ft (1.7m) 17s

Table - best surf conditions forecast for Avellanas Rivermouth over the next 16 days.


The Lowdown

Alright folks, Rusty here. Let’s have a look at what’s shaping up for the next couple of weeks.

We’ve got a solid pulse of groundswell rolling in at Avellanas Rivermouth, but it’s a bit of a mixed bag with the wind. The water is a touch warmer than normal for this time of year, sitting at 86°F, which is a nice bonus.

The standout window is Tuesday, July 28th. The morning starts with a 6 ft swell from the SW, with a very long period of 18 seconds – that’s proper groundswell energy. The combined energy is a strong 1826, so there’s plenty of push. The wind is a light cross-on from the ENE at 6 mph, which is manageable. But the real magic happens in the afternoon: the wind swings to a cross-offshore from the SW at 9 mph, cleaning it right up. The swell stays at 6 ft with a 17-second period, and the energy is 1733. This is excellent for experienced surfers – the rivermouth will be handling that long-period swell beautifully. Crowds are likely here, so get your timing right.

Wednesday, July 29th, is also a good call. The swell drops a touch to 5 ft, still with a long 16-second period from the SW. The afternoon session looks best again, with that cross-off SW wind at 9 mph keeping things clean (energy 1205). The mornings are a bit choppy with a cross-on NE breeze.

After that, the swell fades. Thursday, July 30th, sees the morning wrecked by a 16 mph ENE cross-on wind, making it a write-off. The afternoon is cleaner with a 4 ft SW swell and light cross-off wind, but it’s much smaller. By Friday, July 31st, the swell drops to 3 ft, and the weekend is small – 3 ft on Saturday and 2 ft by Sunday. The only bright spot there is Sunday, August 2nd, morning: a glassy 2 ft swell with a 15-second period and light ESE wind. It’s clean but tiny, so only for the longboard or a fun fish.

The first week of August looks pretty flat. We’ve got a gap of several days here with no real recommendations. The swell struggles to get above 3 ft, and mornings are mostly blown out by strong ENE winds. The afternoons are often clean but the waves are small and weak. The combined energy drops into the low hundreds, showing a real lack of punch.

There is a flicker of hope on Saturday, August 8th, in the afternoon. The swell builds to 3 ft from the SW with a 15-second period, and the wind goes completely glassy – calm at 0 mph. The energy is 549, which is moderate. It’s the cleanest option in that second week, but it’s a long way out, so keep an eye on it.

Tuesday, August 12th, sees a new pulse of SW swell arriving with an 18-second period and 3 ft height. The afternoon has a cross-off wind, but the energy is a solid 880. It’s promising, but it’s more than a week away, so don’t lock it in yet.

Overall, hit Tuesday afternoon, July 28th, and Wednesday afternoon, July 29th, for the best waves. The rest of the run is a waiting game.

Rusty.

Short Range Forecast

Mostly dry. Warm (max 33°C on Thu morning, min 25°C on Tue night). Wind will be generally light.

Days 4-6 Weather Summary

Heavy rain (total 26mm), heaviest during Sun afternoon. Warm (max 31°C on Sat morning, min 26°C on Fri night). Wind will be generally light.

Tuesday
28
Wednesday
29
Thursday
30
Friday
31
Saturday
1
Sunday
2
Monday
3
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
AM
PM
Night
Rating
(10 max)
2
4
4
2
4
1
0
3
1
0
1
1
0
2
0
2
2
2
1
2
2
Swell
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Height Map
Wave
Height (m)
Direction
Period (s)
1.7
SW
18
1.7
SW
17
1.7
SW
16
1.6
SW
16
1.6
SW
16
1.4
SW
15
1.3
SW
14
1.2
SW
14
1.1
SW
14
1
SW
14
1
SW
13
1
SW
13
0.9
SW
13
0.9
SW
13
0.7
SW
12
0.6
SW
15
0.6
SW
15
0.6
SW
14
0.8
SW
14
0.8
SW
13
0.6
SSW
13
Wave Graph
Metric surfscale
Energy kJ
1741
1682
1456
1194
1149
856
667
589
485
357
342
326
238
234
147
134
171
167
228
208
111
Wind (km/h)
10
ENE
15
SW
5
E
15
NE
10
SW
10
ENE
25
ENE
10
SSW
15
ENE
15
ENE
20
SW
10
E
15
ENE
15
SW
10
E
0
ESE
10
SW
5
SSE
10
E
15
WSW
0
WSW
Wind State
cross-on
cross-off
glassy
cross-on
cross-off
cross-on
cross-on
cross-off
on
cross-on
cross-off
on
cross-on
cross-off
on
glassy
cross-off
glassy
on
cross-off
glassy
High Tide
1:59PM2.16m
2:35AM2.01m
2:41PM2.23m
3:15AM2.12m
3:20PM2.28m
3:52AM2.22m
3:58PM2.30m
4:27AM2.30m
4:35PM2.29m
5:02AM2.35m
5:11PM2.26m
5:37AM2.38m
5:50PM2.20m
Low Tide
8:25PM0.43m
8:31AM0.59m
9:03PM0.35m
9:13AM0.53m
9:38PM0.31m
9:52AM0.48m
10:12PM0.28m
10:30AM0.44m
10:46PM0.28m
11:08AM0.42m
11:19PM0.30m
11:47AM0.42m
11:55PM0.34m
part cloud
part cloud
clear
part cloud
part cloud
clear
clear
part cloud
clear
clear
part cloud
thunderstorm
part cloud
thunderstorm
thunderstorm
part cloud
thunderstorm
thunderstorm
part cloud
thunderstorm
thunderstorm
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
5:31
5:31
5:31
5:31
5:31
5:31
5:31
<span class="translation_missing" title="translation missing: en.weather_tables.sunset">Sunset</span>
6:07
6:07
6:07
6:06
6:06
6:06
6:06
 mm
3
3
4
15
1
3
2
Temp °C
31
29
27
31
29
27
33
30
28
30
29
28
31
29
27
31
28
27
30
29
28
Feels °C
34
31
31
34
32
30
35
33
31
32
31
32
34
32
31
35
31
32
33
32
32
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  • 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 Avellanas Rivermouth Surf forecast

The above surf forecast table for Avellanas Rivermouth provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Avellanas Rivermouth can be found by selecting the local surf guide option on the grey menu. Our Avellanas Rivermouth 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 (Avellanas Rivermouth) 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 Avellanas Rivermouth 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.

Avellanas Rivermouth is 44 km (27 miles) from Nicoya. If you plan a holiday in Guanacaste, look for hotels and other accommodation in Nicoya. Nicoya has rooms for a wide range of budgets as well as car hire and transport links.

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