Surf Forecasts:
Costellos surf forecast from 12 Aug 2026:
- Best quality surf: Thursday 13 Aug, 5PM (local time) - 3.5ft (1.0m), 5s period, S swell with offshore winds.
- Most powerful swell: Sunday 16 Aug, 11PM (local time) - 4.5ft (1.3m), 6s period, S swell with 106 kJ wave energy.
- Next surfable swell (1★+): Thursday 13 Aug, 5PM (local time) - 3.5ft (1.0m), 5s period with S swell.
Best Forecast Surf Conditions for Costellos this week:
The surf forecast for Costellos over the next 16 days: The first swell (rated 1 star or higher) is forecast to arrive on Thursday (Aug 13) at 5PM. The primary swell is predicted to be 1.0m and 5s period with a secondary swell of 0.8m and 5s. Another secondary swell of 0.1m and 4s is also forecast. The wind is predicted to be offshore as the swell arrives.
The most powerful waves expected at Costellos in the next 16 days are 1.3m 6s and forecast to arrive on Sunday (Aug 16) at 11PM. 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 4s period and expected on Thursday (Aug 13) at 11AM.
| Wave Type | Time (EDT) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 5PM (Thu 13th Aug) | 3.5ft (1.0m) 5s |
| Best Surf | 5PM (Thu 13th Aug) | 3.5ft (1.0m) 5s |
| Most Powerful | 11PM (Sun 16th Aug) | 4.5ft (1.3m) 6s |
Table - best surf conditions forecast for Costellos over the next 16 days.
The Lowdown
Alright, mate, Rusty here. Let’s have a look at what’s on the cards for the next couple of weeks.
Honestly, it’s a pretty grim stretch ahead. We’ve got a long, quiet run with barely any surf to speak of until the very end of the period. The first few days are a total write-off, with tiny, weak swell and mostly average to poor conditions. There’s a solid gap of over a week with nothing worthwhile. The only real glimmer of light arrives right at the tail end, around Thursday the 27th of August, and even then, it’s not a classic.
Let’s start with the only spot worth mentioning: Costellos (reef). The water is sitting at 71° – that’s a touch warmer than normal for this time of year, so you might not need the thickest wetsuit.
The opening days from Wednesday the 12th right through to nearly the end of the month are all showing poor surf. The swell is tiny, often under 2 ft, coming from the SE with short periods – just a weak, unorganised mess. Combined energy values are mostly in the low double digits (12 to 48), which is very weak. The wind is all over the place, but there’s nothing that makes it worth paddling out. It’s a real desert.
Then, on Thursday the 27th of August, we get a bit of a pulse. The morning shows a bump to 5 ft swell from the ESE with a period of 8 seconds, and combined energy jumps to 344, which is moderate. The wind is a cross-onshore from the NNE at 9 mph, so it’ll be a bit bumpy. The afternoon sees 5 ft swell from the same direction, period still 8 seconds, energy at 299, but the wind goes full onshore from the ESE at 9 mph, which is not your friend. This is the only time in the whole outlook that the swell cracks over 5 ft, but it’s far from ideal. It’s more of a novelty than a standout. The waves will be messy and hard to read, and with the swell being mostly short-period, it won’t have much power. The reef at Costellos should handle it better than a beach, but the onshore wind will kill the quality.
So, to be honest, this is a two-week period best spent doing other things. The only real chance for a wave is that Thursday the 27th, but don’t expect a classic. It’s more of a “if you’re desperate” situation. The rest is dead flat or close to it. For the way it’s looking, I’d say it’s more interesting for kite surfing than paddle surfing on that Thursday, with the onshore wind and some size.
Stay patient, and keep an eye on the forecasts – it can’t stay this poor forever.
Rusty
Short Range ForecastMostly dry. Warm (max 27°C on Wed afternoon, min 16°C on Sat morning). Wind will be generally light. | Days 5-7 Weather SummaryModerate rain (total 19mm), heaviest on Sun afternoon. Warm (max 26°C on Mon afternoon, min 17°C on Sun afternoon). Wind will be generally light. | |||||||||||||||||||
Wed 12 | Thursday 13 | Friday 14 | Saturday 15 | Sunday 16 | Monday 17 | Tuesday 18 | ||||||||||||||
PM | 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) | SE 14 | S 4 | SE 14 | S 5 | ESE 10 | SE 10 | SE 10 | N 4 | SE 12 | ESE 9 | SE 9 | SE 9 | S 5 | SSE 6 | SSE 5 | SE 7 | SE 8 | SE 8 | SE 8 | SE 6 |
Wave Graph | ||||||||||||||||||||
8 | 8 | 8 | 51 | 9 | 15 | 14 | 9 | 6 | 8 | 3 | 3 | 52 | 77 | 19 | 27 | 29 | 32 | 41 | 18 | |
Wind (km/h) | ||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-off | off | cross-off | off | cross-off | cross-off | cross-off | cross-off | cross-on | cross | cross-off | cross-off | cross | cross-off | cross | glassy | cross-off | glassy | cross | cross-off |
High Tide | 11:38PM3.78m | 12:13PM3.52m | 00:30AM3.77m | 1:01PM3.57m | 1:20AM3.68m | 1:48PM3.56m | 2:09AM3.52m | 2:34PM3.49m | 2:58AM3.32m | 3:20PM3.38m | 3:47AM3.10m | 4:07PM3.23m | 4:39AM2.89m | |||||||
Low Tide | 5:24PM0.31m | 6:00AM0.01m | 6:17PM0.23m | 6:49AM0.03m | 7:08PM0.21m | 7:35AM0.12m | 7:58PM0.25m | 8:21AM0.28m | 8:47PM0.35m | 9:06AM0.47m | 9:37PM0.49m | 9:52AM0.68m | 10:28PM0.64m | |||||||
— | — | 5:46 | — | — | 5:47 | — | — | 5:48 | — | — | 5:48 | — | — | 5:50 | — | — | 5:50 | — | — | |
7:50 | — | — | 7:47 | — | — | 7:46 | — | — | 7:45 | — | — | 7:44 | — | — | 7:43 | — | — | 7:40 | — | |
mm | — | — | — | — | — | — | — | — | — | — | — | — | 9 | 10 | — | — | — | — | — | — |
Temp °C | 27 | 24 | 25 | 27 | 25 | 22 | 25 | 22 | 20 | 23 | 21 | 24 | 22 | 18 | 24 | 26 | 23 | 23 | 24 | 21 |
Feels °C | 26 | 23 | 25 | 27 | 23 | 17 | 20 | 18 | 18 | 20 | 18 | 22 | 19 | 20 | 25 | 27 | 23 | 23 | 21 | 19 |
Swell 1 Height (m) Direction Period (s) | SE 8 | S 4 | SE 8 | SSE 5 | SSE 4 | SE 10 | SE 10 | ESE 9 | SE 9 | ESE 9 | SE 9 | SE 9 | SE 9 | — | SSE 5 | SE 7 | SE 8 | SE 8 | SE 8 | SE 6 |
3 | 4 | 3 | 31 | 4 | 15 | 14 | 8 | 3 | 8 | 3 | 3 | 3 | — | 19 | 27 | 29 | 32 | 41 | 18 | |
Swell 2 Height (m) Direction Period (s) | SE 14 | SE 8 | SE 14 | SW 4 | ESE 10 | SE 13 | SE 13 | SE 12 | SE 12 | — | SE 7 | SE 7 | — | — | SE 9 | ESE 4 | — | SE 14 | SE 13 | SE 8 |
8 | 3 | 8 | 1 | 9 | 7 | 7 | 6 | 6 | — | 2 | 2 | — | — | 3 | 2 | — | 8 | 7 | 11 | |
Swell 3 Height (m) Direction Period (s) | E 11 | SE 14 | E 10 | SE 10 | SE 13 | — | S 6 | — | E 12 | E 12 | — | S 6 | — | — | — | — | — | E 14 | — | SE 12 |
2 | 8 | 2 | 4 | 7 | — | 1 | — | 3 | 3 | — | 1 | — | — | — | — | — | 4 | — | 6 | |
Wind waves Height (m) Direction Period (s) | SSE 3 | SSW 4 | S 4 | S 5 | NW 2 | NW 3 | NW 3 | N 4 | NNE 4 | — | SSW 4 | S 3 | S 5 | SSE 6 | — | — | NNE 3 | — | — | — |
2 | 8 | 18 | 51 | 2 | 2 | 3 | 9 | 3 | — | 5 | 1 | 52 | 77 | — | — | 2 | — | — | — | |
Nearest Offshore or Glassy | ||||||||||||||||||||
Distance (km) | 501 | 501 | 38 | 0 | 2579 | 620 | 3534 | 627 | 2804 | 503 | 1898 | 620 | 588 | 0 | 162 | 182 | 168 | 186 | 787 | 227 |
Best forecast wave conditions in New Hampshire | ||||||||||||||||||||
Best forecast wave conditions in United States | ||||||||||||||||||||
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Information about the Costellos Surf forecast
The above surf forecast table for Costellos provides essential information for determining whether the surfing conditions will be good over the next 16 days. A general guide to surfing at Costellos can be found by selecting the local surf guide option on the grey menu. Our Costellos 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 (Costellos) 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 Costellos 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.
Costellos is 5 km (3 miles) from Hampton. If you plan a vacation in New Hampshire, look for hotels and other accommodation in Hampton. Hampton has rooms for a wide range of budgets as well as car hire and transport links.











