Surf Forecasts:
Avellanas Rivermouth surf forecast from 13 Jul 2026:
- Best quality surf: Monday 13 Jul, 3PM (local time) - 2ft (0.6m), 14s period, SSW swell with glassy winds.
- Most powerful swell: Sunday 19 Jul, 9AM (local time) - 3.5ft (1.0m), 13s period, S swell with 355 kJ wave energy.
- Next surfable swell (1★+): Monday 13 Jul, 3PM (local time) - 2ft (0.6m), 14s period with SSW 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 Monday (Jul 13) at 3PM. The primary swell is predicted to be 0.5m and 16s period with a secondary swell of 0.6m and 14s. Another secondary swell of 0.5m and 7s 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 1.0m 13s and forecast to arrive on Sunday (Jul 19) at 9AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.8m 5s period and expected on Wednesday (Jul 15) at 12AM.
| Wave Type | Time (CST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 3PM (Mon 13th Jul) | 2ft (0.6m) 14s |
| Best Surf | 3PM (Mon 13th Jul) | 2ft (0.6m) 14s |
| Most Powerful | 9AM (Sun 19th Jul) | 3.5ft (1.0m) 13s |
Table - best surf conditions forecast for Avellanas Rivermouth over the next 16 days.
Alright folks, Rusty here. Let’s take a long look at what’s coming down the pipe for the next couple of weeks. We’re only looking at one spot, Avellanas Rivermouth, so that’s our focus for this whole stretch.
Right off the bat, we’ve got a bit of a waiting game. The first solid recommendation doesn’t show up until Monday afternoon, July 13th. The surf before that is pretty marginal, so don't bother paddling out just yet.
The best of the early action is going to be Monday afternoon, July 13th. The wind goes glassy from the north, which will make the surface buttery smooth. You’re looking at small but clean 2ft S swell with a very long 16-second period. That long period means it’s proper groundswell, and at a rivermouth, that can set up some nice little lines. The combined wave energy is moderate at 279.
After that, things get a bit choppy and messy for a few days with onshore winds dominating. We get a few brief windows: Wednesday afternoon, July 15th offers a clean 2ft SW swell (16s period) with a light cross-offshore breeze, and Thursday afternoon, July 16th bumps up a touch to 3ft from the SSW (13s) with a clean cross-offshore. Not huge, but surfable and clean.
Now, for the true standout of this whole forecast, you have to look ahead. Sunday afternoon, July 26th and Monday afternoon, July 27th are looking exceptional. On Sunday the 26th, we’ve got a clean 2ft SW swell with a very long 19-second period and a light cross-offshore wind. The water is "a touch warmer than normal" at 86°. Then on Monday the 27th, it gets even better: a clean 3ft SW swell with an 18-second period, paired with a light offshore wind from the west. This is going to be smooth, lined-up, and very surf-friendly. The combined energy on the 27th is moderate at 662.
The crowd factor at Avellanas Rivermouth? It says crowds are "often" here, so expect company, especially on those clean afternoons. It’s an intermediate sandbar break that’s "fairly consistent".
In the middle of it all, keep an eye on Saturday, July 25th. The morning is a bit iffy, but Saturday afternoon goes glassy, with a 2ft SW groundswell at a massive 21-second period. The combined energy is moderate at 310. That’s a very long period, which will make the waves feel punchy and well-shaped at the rivermouth.
So, while there are some small windows earlier, the real gold is waiting at the end of the month. Don't sleep on that Sunday-Monday combo.
Rusty.
Short Range ForecastLight rain (total 4mm), mostly falling on Mon afternoon. Warm (max 30°C on Mon morning, min 24°C on Tue night). Wind will be generally light. | Days 5-7 Weather SummaryLight rain (total 6mm), mostly falling on Thu afternoon. Warm (max 31°C on Fri morning, min 25°C on Wed night). Wind will be generally light. | ||||||||||||||||||||
Sun 12 | Monday 13 | Tuesday 14 | Wednesday 15 | Thursday 16 | Friday 17 | Saturday 18 | |||||||||||||||
PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | PM | Night | AM | |
Swell Height Map |  |  |  |  |  |  |  |  | |||||||||||||
Wave Height (m) Direction Period (s) | SSW 14 | SW 13 | SW 14 | SSW 14 | S 15 | S 15 | SSW 14 | SSW 13 | SSW 13 | SW 16 | SW 16 | SSW 12 | SSW 13 | S 14 | S 14 | SSW 13 | SSW 13 | SSW 12 | SSW 12 | SSW 13 | S 13 |
Wave Graph  | |||||||||||||||||||||
 kJ | 318 | 164 | 200 | 132 | 159 | 155 | 207 | 144 | 181 | 196 | 206 | 196 | 326 | 203 | 195 | 229 | 232 | 206 | 164 | 286 | 355 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross | on | cross-on | glassy | on | on | on | cross-on | on | cross-off | cross-on | on | cross-off | on | cross-on | on | cross-on | cross-on | glassy | on | cross-on |
High Tide | 1:01AM2.12m | 1:21PM2.52m | 2:01AM2.26m | 2:19PM2.59m | 2:57AM2.41m | 3:13PM2.63m | 3:50AM2.52m | 4:05PM2.62m | 4:40AM2.59m | 4:55PM2.56m | 5:28AM2.59m | 5:43PM2.45m | 6:15AM2.54m | ||||||||
Low Tide | 6:51PM0.26m | 7:00AM0.37m | 7:49PM0.14m | 8:02AM0.28m | 8:43PM0.03m | 9:00AM0.20m | 9:34PM-0.03m | 9:55AM0.16m | 10:23PM-0.05m | 10:47AM0.16m | 11:10PM0.00m | 11:38AM0.21m | 11:56PM0.10m | ||||||||
 |  | |  | | | | | | | | | | |  | | | | |  | | |
 | — | — | 5:28 | — | — | 5:28 | — | — | 5:28 | — | — | 5:28 | — | — | 5:28 | — | — | 5:28 | — | — | 5:30 |
 | 6:08 | — | — | 6:08 | — | — | 6:08 | — | — | 6:08 | — | — | 6:08 | — | — | 6:08 | — | — | 6:08 | — | 6:08 |
mm | — | — | — | 3 | — | — | 1 | — | — | 1 | — | — | 3 | — | — | 2 | — | — | 7 | 2 | — |
Temp °C | 29 | 26 | 30 | 30 | 26 | 30 | 30 | 26 | 30 | 28 | 27 | 30 | 28 | 27 | 31 | 30 | 26 | 30 | 29 | 26 | 31 |
Feels °C | 32 | 27 | 32 | 34 | 28 | 32 | 33 | 27 | 33 | 31 | 31 | 35 | 32 | 31 | 32 | 32 | 27 | 31 | 33 | 29 | 31 |
Swell 1 Height (m) Direction Period (s) | SSW 14 | S 7 | SW 14 | SSW 14 | S 15 | S 15 | SSW 14 | N 5 | SSW 13 | SW 16 | SW 16 | SSW 12 | SSW 13 | S 14 | S 14 | SSW 13 | SSW 13 | SSW 12 | SSW 12 | SSW 13 | S 13 |
| kJ | 318 | 47 | 200 | 125 | 159 | 155 | 207 | 36 | 181 | 196 | 206 | 196 | 326 | 203 | 195 | 229 | 232 | 206 | 164 | 286 | 355 |
Swell 2 Height (m) Direction Period (s) | S 7 | SW 13 | S 7 | S 7 | N 4 | SW 13 | SW 13 | SSW 13 | SW 14 | SSW 13 | SW 13 | SW 16 | SW 16 | SW 12 | SW 12 | SW 15 | SW 13 | S 14 | S 14 | S 6 | S 7 |
| kJ | 37 | 164 | 35 | 22 | 9 | 140 | 140 | 139 | 164 | 129 | 80 | 91 | 40 | 68 | 67 | 76 | 140 | 150 | 146 | 12 | 22 |
Swell 3 Height (m) Direction Period (s) | SW 6 | SSW 14 | S 16 | S 16 | SW 13 | S 6 | SW 18 | SW 13 | N 5 | SSW 16 | N 5 | S 13 | WSW 20 | SW 14 | SW 15 | SW 12 | S 16 | SW 18 | SW 19 | SW 19 | SW 19 |
| kJ | 10 | 63 | 134 | 132 | 88 | 18 | 152 | 144 | 13 | 86 | 11 | 89 | 39 | 103 | 75 | 52 | 81 | 113 | 129 | 96 | 217 |
Wind waves Height (m) Direction Period (s) | N 4 | NNE 4 | — | — | — | NNE 4 | — | — | — | — | — | NNE 5 | — | N 4 | NNE 5 | N 5 | NNE 4 | NNE 5 | N 5 | NNE 5 | NNE 3 |
| kJ | 3 | 15 | — | — | — | 3 | — | — | — | — | — | 5 | — | 10 | 24 | 16 | 19 | 37 | 8 | 19 | 6 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 8 | 1 | 10 | 0 | 1 | 1 | 1 | 19 | 1 | 0 | 1 | 1 | 0 | 1 | 19 | 1 | 10 | 19 | 0 | 1 | 19 |
Best forecast wave conditions in Guanacaste | |||||||||||||||||||||
Best forecast wave conditions in Costa Rica | |||||||||||||||||||||
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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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