Surf Forecasts:
Avellanas Rivermouth surf forecast from 16 Jul 2026:
- Most powerful swell: Tuesday 21 Jul, 3AM (local time) - 3.5ft (1.0m), 15s period, SW swell with 415 kJ wave energy.
Best Forecast Surf Conditions for Avellanas Rivermouth this week:
The most powerful waves expected at Avellanas Rivermouth in the next 16 days are 1.0m 15s and forecast to arrive on Tuesday (Jul 21) at 3AM. Winds are predicted to be cross-onshore at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.7m 5s period and expected on Tuesday (Jul 21) at 3PM.
| Wave Type | Time (CST) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | - | - |
| Best Surf | - | - |
| Most Powerful | 3AM (Tue 21st Jul) | 3.5ft (1.0m) 15s |
Table - best surf conditions forecast for Avellanas Rivermouth over the next 16 days.
The Lowdown
Alright, let’s look at Avellanas Rivermouth. The first week’s a bust – from Thursday July 16 through Wednesday July 22, it’s all cross-onshore wind, lumpy and choppy, with tiny swell. Scores are flat. Thursday 23 and Friday 24 July stay marginal, not worth it. That’s about eight days of nothing.
Then things turn. Saturday July 25 afternoon shows a light cross-offshore breeze and clean 3ft SW groundswell with a 20-second period – promising but still just marginal. Sunday July 26 is a washout with heavy rain and cross-on wind.
The real window opens Monday July 27 afternoon: a gentle offshore breeze from the WSW, 4ft SW swell at 19 seconds, clean, combined energy 1302 – solid. Tuesday July 28 afternoon is better: offshore west wind, 5ft SW groundswell at 17 seconds, energy 1604 – that’s expert territory, maybe too big for beginners. Wednesday July 29 morning is glassy calm, 5ft SW at 16 seconds, 1123 energy. Thursday July 30 morning and afternoon both glassy, 4ft SW at 15 seconds, energy around 700-739. Clean and fun.
Long periods (15-19 seconds) mean proper groundswell with shape and longer lulls, which works well at a rivermouth. Crowds are common here, so expect company on the good days.
Best bet: Tuesday July 28 afternoon or Wednesday July 29 morning. That’s the standout.
Rusty
Short Range ForecastSome drizzle, heaviest during Sat afternoon. Warm (max 31°C on Thu morning, min 25°C on Wed night). Winds decreasing (fresh winds from the ENE on Fri morning, light winds from the S by Sat afternoon). | Days 5-7 Weather SummaryMostly dry. Warm (max 32°C on Sun morning, min 25°C on Sun night). Mainly fresh winds. | ||||||||||||||||||
Thursday 16 | Friday 17 | Saturday 18 | Sunday 19 | Monday 20 | Tuesday 21 | ||||||||||||||
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) | SW 16 | SW 13 | SSW 13 | S 14 | S 14 | SSW 13 | S 13 | SSW 12 | SSW 12 | S 13 | S 13 | SSW 12 | S 12 | SW 16 | SW 16 | SW 15 | SW 15 | SW 14 | SW 13 |
Wave Graph  | |||||||||||||||||||
 kJ | 206 | 172 | 326 | 203 | 195 | 178 | 222 | 192 | 164 | 350 | 276 | 248 | 243 | 366 | 361 | 313 | 301 | 206 | 250 |
Wind (km/h) | |||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross | cross-on | cross-on | on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on | cross-on |
High Tide | 3:50AM2.52m | 4:05PM2.62m | 4:40AM2.59m | 4:55PM2.56m | 5:28AM2.59m | 5:43PM2.45m | 6:15AM2.54m | 6:31PM2.31m | 7:02AM2.45m | 7:20PM2.15m | 7:48AM2.33m | 8:10PM2.00m | |||||||
Low Tide | 9:34PM-0.03m | 9:55AM0.16m | 10:23PM-0.05m | 10:47AM0.16m | 11:10PM0.00m | 11:38AM0.21m | 11:56PM0.10m | 12:28PM0.30m | 00:41AM0.24m | 1:19PM0.40m | 1:27AM0.40m | 2:10PM0.51m | 2:15AM0.55m | ||||||
 |  | |  | | | |  |  | | | | | | | | | | | |
 | — | 5:28 | — | — | 5:28 | — | — | 5:28 | — | — | 5:30 | — | — | 5:30 | — | — | 5:30 | — | — |
 | — | — | 6:08 | — | — | 6:08 | — | — | 6:08 | — | — | 6:08 | — | — | 6:07 | — | — | 6:07 | — |
mm | — | — | — | — | — | — | — | — | 1 | — | — | — | — | — | — | — | — | — | — |
Temp °C | 27 | 31 | 31 | 28 | 31 | 30 | 28 | 31 | 31 | 27 | 32 | 32 | 27 | 30 | 29 | 27 | 27 | 25 | 26 |
Feels °C | 30 | 32 | 33 | 27 | 31 | 32 | 27 | 32 | 35 | 28 | 32 | 33 | 26 | 29 | 28 | 27 | 27 | 26 | 24 |
Swell 1 Height (m) Direction Period (s) | SW 16 | SW 13 | SSW 13 | S 14 | S 14 | SSW 13 | S 13 | SSW 12 | SSW 12 | S 13 | S 13 | SSW 12 | S 12 | SW 16 | SW 16 | SW 15 | SW 15 | SW 14 | SW 13 |
| kJ | 206 | 172 | 326 | 203 | 195 | 178 | 222 | 192 | 164 | 350 | 276 | 248 | 243 | 366 | 361 | 313 | 301 | 206 | 250 |
Swell 2 Height (m) Direction Period (s) | SW 13 | S 12 | N 5 | SW 12 | SW 12 | SW 15 | SW 13 | S 14 | S 14 | SW 19 | SW 19 | SW 18 | S 6 | S 13 | S 12 | S 12 | S 12 | N 5 | SSW 7 |
| kJ | 80 | 77 | 8 | 68 | 67 | 76 | 140 | 150 | 146 | 96 | 170 | 194 | 20 | 212 | 190 | 144 | 137 | 25 | 51 |
Swell 3 Height (m) Direction Period (s) | S 12 | SW 16 | SW 16 | SW 14 | SW 15 | SW 12 | S 16 | SW 18 | SW 19 | SW 13 | S 7 | S 7 | SW 18 | S 7 | S 6 | S 6 | SSW 7 | SSW 7 | S 12 |
| kJ | 72 | 91 | 40 | 103 | 75 | 52 | 81 | 113 | 129 | 28 | 23 | 21 | 192 | 23 | 21 | 22 | 36 | 37 | 101 |
Wind waves Height (m) Direction Period (s) | NNE 5 | N 5 | — | NNE 4 | NNE 4 | N 5 | NNE 4 | NNE 5 | N 5 | NNE 4 | NNE 5 | N 5 | NNE 4 | NNE 5 | N 5 | NNE 4 | NNE 5 | — | NNE 4 |
| kJ | 14 | 13 | — | 13 | 21 | 19 | 24 | 33 | 12 | 10 | 19 | 7 | 19 | 17 | 11 | 23 | 46 | — | 10 |
Nearest Offshore or Glassy | |||||||||||||||||||
Distance (km) | 19 | 19 | 1 | 19 | 19 | 7 | 19 | 19 | 8 | 19 | 19 | 1 | 19 | 19 | 19 | 19 | 19 | 19 | 19 |
Best forecast wave conditions in Guanacaste | |||||||||||||||||||
Best forecast wave conditions in Costa Rica | |||||||||||||||||||
Header Global | |||||||||||||||||||
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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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