Avellanas Rivermouth Surf Break

Lat Long: 10.24° N 85.84° W

Avellanas Rivermouth Surf Forecast and Surf Report

Issued: 11 pm 21 Jul 2026 (local time)

Forecast update in  hr  min

Today's Avellanas Rivermouth sea temperature is
30.0° 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 22 Jul 2026:

  • Best quality surf: Sunday 26 Jul, 12PM (local time) - 4.5ft (1.3m), 18s period, SW swell with glassy winds.
  • Most powerful swell: Tuesday 28 Jul, 12PM (local time) - 6ft (1.8m), 17s period, SW swell with 1,858 kJ wave energy.
  • Next surfable swell (1★+): Thursday 23 Jul, 3PM (local time) - 1.5ft (0.4m), 26s 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 Thursday (Jul 23) at 3PM. The primary swell is predicted to be 0.4m and 26s period with a secondary swell of 1.2m and 8s. Another secondary swell of 0.4m and 13s is also forecast. The wind is predicted to be glassy as the swell arrives.

The most powerful waves expected at Avellanas Rivermouth in the next 16 days are 1.8m 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 0.7m 5s period and expected on Saturday (Jul 25) at 9AM.

Wave TypeTime (CST) & Date Wave Height & Period
Next good surf (1 star+) 3PM (Thu 23rd Jul)1.5ft (0.4m) 26s
Best Surf12PM (Sun 26th Jul)4.5ft (1.3m) 18s
Most Powerful12PM (Tue 28th Jul)6ft (1.8m) 17s

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


The Lowdown

Alright, this is Rusty. Let's talk about what's on the menu at Avellanas Rivermouth.

First up, the water temp is about average for this time of year, nothing out of the ordinary. We're looking at a bit of a slow start, but things will fire up.

The week starts pretty flat. Wednesday morning, July 22nd, is a write-off with a weak 2ft SW swell and a cross-onshore wind making it a choppy mess. The energy is pathetic (282). Thursday morning, July 23rd, is just as bad. But then, hold onto your boards, Thursday afternoon things get interesting. A tiny 1ft swell rolls in, but it's a long-period groundswell of 26 seconds, and the wind goes glassy. That's a recipe for clean, silky lines at a rivermouth. The energy is moderate (392), but the quality will be there for the patient surfer.

Friday, July 24th, is a letdown. The swell bumps up to 3ft in the morning, but the wind is cross-onshore, ruining it. Saturday, July 25th, is a bit of a mixed bag. The morning is stormy, but the afternoon is the real standout for the near-term. The wind goes glassy, the swell is a solid 3ft from the SW, and the energy is strong (730). This is your best bet for the first few days.

Sunday, July 26th, afternoon is another cracker. The swell pushes to 4ft from the SW, the wind is glassy, and the energy is pumping (1245). Experienced surfers will have a ball. The morning is a bit too choppy with a cross-offshore.

Monday, July 27th, through Tuesday, July 28th, the swell gets bigger, hitting 6ft, but the wind is mostly onshore or cross-onshore, making it a messy, lumpy proposition. 6ft is getting big, and with poor wind, it's a pass unless you're desperate.

Wednesday, July 29th, afternoon is a proper highlight. The swell is a solid 5ft from the SW, but the wind goes cross-offshore, and the energy is strong (1220). That's a clean, powerful wave for experienced surfers.

Thursday, July 30th, afternoon is a good one too. The swell drops to 4ft, but the wind is cross-offshore and clean, with moderate energy (549). A fun, manageable wave.

The following week, from August 1st onwards, the swell drops off steadily. The first weekend sees 3ft waves but mostly onshore winds. The best of the second week looks like Monday afternoon, August 3rd, with a tiny 2ft swell, but the wind goes glassy again. It'll be small but clean for a longboard or a log. The energy is weak (263).

The standout of the whole 16 days is the Sunday, July 26th, afternoon session. 4ft of SW groundswell with glassy conditions and strong energy (1245) is classic Avellanas Rivermouth. The second best is the Wednesday, July 29th, afternoon with the clean 5ft swell.

Rusty, signing off.

Short Range Forecast

Light rain (total 9mm), mostly falling on Tue night. Warm (max 31°C on Fri afternoon, min 25°C on Tue night). Wind will be generally light.

Days 5-7 Weather Summary

Heavy rain (total 29mm), heaviest during Sat afternoon. Warm (max 31°C on Mon afternoon, min 24°C on Fri night). Wind will be generally light.

Wednesday
22
Thursday
23
Friday
24
Saturday
25
Sunday
26
Monday
27
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
2
2
0
1
3
2
3
2
2
4
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)
0.8
SW
13
0.7
SW
13
0.7
SW
13
0.6
SW
12
0.6
SW
12
0.4
SW
26
1.1
SW
8
0.8
SW
24
0.6
SW
24
1.1
SW
21
0.9
SW
21
0.9
SW
20
1.3
SW
19
1.1
SW
19
1.3
SW
18
1.4
SW
17
1.1
SW
19
1.1
SW
19
1.6
SW
18
Wave Graph
Metric surfscale
Energy kJ
250
173
158
92
93
171
176
661
347
1015
756
569
1210
920
1099
1199
791
800
1591
Wind (km/h)
10
ESE
15
ENE
20
E
20
E
15
ENE
5
E
15
W
15
NE
10
NNE
5
ENE
10
NE
5
SW
15
ENE
10
ENE
5
WSW
15
E
20
ENE
10
SE
10
ENE
Wind State
cross-on
cross-on
on
on
on
glassy
off
cross-on
cross-on
cross-on
cross-on
glassy
on
cross-on
glassy
on
cross-on
cross-on
on
High Tide
8:37AM2.20m
9:04PM1.86m
9:29AM2.09m
10:03PM1.77m
10:25AM2.02m
11:07PM1.72m
11:24AM2.00m
00:08AM1.74m
12:21PM2.03m
1:04AM1.81m
1:12PM2.09m
1:52AM1.90m
Low Tide
2:15AM0.55m
3:04PM0.60m
3:06AM0.68m
4:02PM0.67m
4:03AM0.76m
5:03PM0.69m
5:03AM0.80m
6:02PM0.66m
6:03AM0.78m
6:56PM0.59m
6:58AM0.73m
7:43PM0.51m
mod rain
part cloud
cloud
part cloud
cloud
light rain
part cloud
clear
thunderstorm
thunderstorm
thunderstorm
mod rain
thunderstorm
rain showers
thunderstorm
part cloud
part cloud
part cloud
part cloud
<span class="translation_missing" title="translation missing: en.weather_tables.sunrise">Sunrise</span>
5:30
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
6:07
6:07
6:07
 mm
6
1
2
11
2
7
4
1
4
Temp °C
26
29
29
27
30
29
27
30
31
26
28
28
26
30
28
26
30
31
27
Feels °C
28
29
30
26
32
32
31
30
33
29
31
32
28
34
32
27
31
33
31
  • Map Icons:
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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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