Surf Forecasts:
Costellos surf forecast from 21 Aug 2026:
- Best quality surf: Sunday 23 Aug, 11PM (local time) - 5ft (1.5m), 6s period, SSE swell with glassy winds.
- Most powerful swell: Sunday 23 Aug, 11PM (local time) - 5ft (1.5m), 6s period, SSE swell with 139 kJ wave energy.
- Next surfable swell (1★+): Friday 21 Aug, 11PM (local time) - 1.5ft (0.5m), 8s period with ESE 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 Friday (Aug 21) at 11PM. The primary swell is predicted to be 0.5m and 8s period with a secondary swell of 0.3m and 4s. Another secondary swell of 0.4m and 4s is also forecast. The wind is predicted to be glassy as the swell arrives.
The most powerful waves expected at Costellos in the next 16 days are 1.5m 6s and forecast to arrive on Sunday (Aug 23) at 11PM. Winds are predicted to be glassy at the time the swell arrives. The largest open ocean swell (not directed at the beach) is 0.4m 3s period and expected on Tuesday (Aug 25) at 11AM.
| Wave Type | Time (EDT) & Date | Wave Height & Period |
|---|---|---|
| Next good surf (1 star+) | 11PM (Fri 21st Aug) | 1.5ft (0.5m) 8s |
| Best Surf | 11PM (Sun 23rd Aug) | 5ft (1.5m) 6s |
| Most Powerful | 11PM (Sun 23rd Aug) | 5ft (1.5m) 6s |
Table - best surf conditions forecast for Costellos over the next 16 days.
The Lowdown
Gutted to be the bearer of bad news, but the next couple of weeks are looking pretty flat and messy for Costellos (reef). We’ve got a long stretch of small, junky surf ahead, with the onshore winds messing up what little energy there is. The water temp is sitting at 66°F, which is bang on average for this time of year.
The run starts on Friday the 21st and honestly, it’s a write-off. We’ve got a tiny 2ft of swell rolling in from the ESE with only 8 seconds of period, and a cross-on breeze is going to have it all chopped up. The energy is weak at 56. Saturday the 22nd isn’t any better – a bit more push in the afternoon with 4ft, but the period drops to a gutless 6 seconds. It’s all over the place and not worth suiting up for.
We get a small glimmer on Monday the 24th. The wind swings offshore and it cleans right up. The swell is still pretty anemic, only 1ft to 2ft, but at least it’s not a complete washing machine. There’s a slight bump in energy to 109 in the afternoon. Still, “surfable but ordinary” is about the best I can say for it, and it’s going to be inconsistent.
After that, we sink back into the doldrums. From Tuesday the 25th all the way through to the end of the month, we’re looking at swell heights below 2ft and periods that just hover around 8 to 9 seconds. The energy values are mostly in the 20s to 60s, which is just weak. There’s one chance of a clean, glassy morning on Friday the 28th, but with only 2ft on offer, it’s a longboard and a whole lot of patience kind of session.
The first week of September doesn’t offer any salvation either. The swell stays tiny, mostly 0.7ft to 1ft, and the wind is either cross-off or cross-on. Even when it’s clean, there’s just nothing to push you along. The energy readings are pitiful, often in the teens.
Honestly, this is a classic blank run for a spot like this. When it’s this flat and the wind is messy, it’s a waiting game. The small windows of clean conditions on Monday the 24th and Friday the 28th are the only times I’d even bother looking at the ocean, and even then, keep your expectations in the gutter. The long period (from Sunday the 23rd and into Monday the 24th) is decent at 11-12 seconds, but with that tiny size, it’s not doing us any favors at this reef.
Stick the board in the van and go find a flat-water paddle, or just wait it out. These runs don’t last forever, and the forecast can always change.
Rusty
Short Range ForecastModerate rain (total 11mm), heaviest on Sat morning. Warm (max 21°C on Fri morning, min 16°C on Sat morning). Wind will be generally light. | Days 4-6 Weather SummaryMostly dry. Warm (max 26°C on Mon afternoon, min 16°C on Mon night). Wind will be generally light. | ||||||||||||||||||||
Friday 21 | Saturday 22 | Sunday 23 | Monday 24 | Tuesday 25 | Wednesday 26 | Thursday 27 | |||||||||||||||
AM | 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) | ESE 8 | ESE 8 | ESE 8 | ESE 5 | ESE 6 | E 6 | E 6 | ESE 12 | SE 6 | SSE 6 | SE 11 | SE 11 | SE 11 | SE 11 | SE 11 | SE 10 | SE 10 | SE 9 | SE 8 | SE 9 | SE 9 |
Wave Graph  | |||||||||||||||||||||
 kJ | 39 | 38 | 36 | 33 | 82 | 52 | 32 | 28 | 106 | 34 | 32 | 39 | 29 | 29 | 18 | 17 | 15 | 13 | 20 | 23 | 37 |
Wind (km/h) | |||||||||||||||||||||
Wind State on-shore cross-onshore cross-shore cross-offshore off-shore glassy | cross-on | on | cross | cross-on | cross | cross-off | cross-on | cross-on | off | cross-off | off | off | off | off | off | cross-off | cross-on | cross-off | cross | cross-on | cross |
High Tide | 6:45PM2.91m | 7:32AM2.56m | 7:42PM2.90m | 8:28AM2.59m | 8:36PM2.95m | 9:19AM2.66m | 9:26PM3.03m | 10:04AM2.78m | 10:11PM3.13m | 10:45AM2.91m | 10:54PM3.22m | 11:24AM3.04m | 11:35PM3.29m | ||||||||
Low Tide | 12:26PM1.14m | 1:19AM0.92m | 1:24PM1.18m | 2:16AM0.90m | 2:20PM1.15m | 3:08AM0.84m | 3:12PM1.07m | 3:54AM0.74m | 3:59PM0.95m | 4:36AM0.64m | 4:43PM0.82m | 5:14AM0.55m | 5:24PM0.69m | ||||||||
 |  |  |  | |  | |  |  | | | | | |  | | | | | | | |
 | 5:54 | — | — | 5:56 | — | — | 5:56 | — | — | 5:58 | — | — | 5:58 | — | — | 6:00 | — | — | 6:01 | — | — |
 | — | 7:36 | — | — | 7:35 | — | — | 7:32 | — | — | 7:31 | — | — | 7:30 | — | — | 7:28 | — | — | 7:27 | — |
mm | — | — | — | 3 | 4 | — | — | 1 | 3 | — | — | — | — | — | — | — | — | — | — | — | — |
Temp °C | 21 | 21 | 19 | 17 | 16 | 16 | 19 | 20 | 20 | 24 | 26 | 23 | 22 | 23 | 20 | 22 | 25 | 21 | 23 | 23 | 20 |
Feels °C | 18 | 18 | 19 | 15 | 13 | 15 | 20 | 20 | 23 | 22 | 22 | 21 | 19 | 20 | 17 | 19 | 24 | 18 | 21 | 19 | 17 |
Swell 1 Height (m) Direction Period (s) | ESE 8 | ESE 8 | ESE 8 | ESE 5 | ESE 6 | E 6 | E 6 | E 6 | SE 6 | SSE 6 | SSE 6 | SE 6 | SE 6 | SE 11 | ESE 7 | SE 10 | ESE 6 | ESE 7 | SE 8 | SE 7 | SE 9 |
| kJ | 39 | 38 | 36 | 33 | 82 | 52 | 32 | 15 | 106 | 34 | 27 | 39 | 10 | 29 | 9 | 17 | 8 | 9 | 20 | 13 | 37 |
Swell 2 Height (m) Direction Period (s) | SE 15 | SE 14 | ESE 14 | ESE 8 | ESE 8 | ESE 13 | ESE 12 | ESE 12 | ESE 12 | E 7 | E 6 | E 6 | E 6 | SE 6 | SSE 6 | SE 6 | SE 10 | S 3 | ESE 10 | SE 9 | E 11 |
| kJ | 8 | 8 | 18 | 24 | 20 | 16 | 15 | 28 | 14 | 14 | 20 | 13 | 7 | 5 | 7 | 5 | 15 | 2 | 10 | 23 | 2 |
Swell 3 Height (m) Direction Period (s) | E 15 | E 14 | SE 14 | ESE 13 | ESE 13 | ESE 8 | SE 9 | ESE 7 | SE 12 | ESE 6 | SE 11 | SE 11 | SE 11 | E 6 | SE 11 | ESE 6 | SE 6 | SE 9 | E 11 | E 11 | — |
| kJ | 4 | 4 | 7 | 17 | 17 | 6 | 3 | 10 | 6 | 15 | 32 | 30 | 29 | 7 | 18 | 4 | 1 | 13 | 3 | 2 | — |
Wind waves Height (m) Direction Period (s) | NE 3 | E 4 | ENE 4 | NE 4 | NNE 4 | NNE 4 | — | — | — | SW 3 | SSE 6 | — | SW 3 | SSW 3 | W 3 | WNW 3 | — | SW 3 | — | SSE 2 | S 4 |
| kJ | 5 | 7 | 1 | 11 | 12 | 5 | — | — | — | 1 | 30 | — | 2 | 1 | 2 | 1 | — | 2 | — | 1 | 19 |
Nearest Offshore or Glassy | |||||||||||||||||||||
Distance (km) | 493 | 855 | 5 | 855 | 44 | 0 | 910 | 416 | 0 | 0 | 0 | 0 | 910 | 14 | 227 | 1296 | 1290 | 493 | 619 | 951 | 493 |
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.
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