CatchWindow fishing intelligence

Nantucket Island, MA Daily Water Report — August 28, 2026

Today's best bet is diving, and it's not even close. An 8.5 out of 10 makes this the standout window on Nantucket Island, with the surface cooperating beautifully for anyone planning to spend time below it. The southeast breeze holds at just 4 knots, gusting to 11, and seas are a manageable 0.86 meters on a 5.6-second period. That wave action is modest enough that even the midday ebb—low tide hits at 18:47, but the afternoon low water around 13:14 is almost as flat—should leave nearshore ledges and rips settled. Water temperature sits at 20.9°C, which is a hair above the seasonal average, and the past week has consistently delivered diving scores above 8.4, so this run of calm conditions is no fluke. Visibility data isn't directly available, but with light wind and low swell, the odds are in your favor. Fishing also scores well at 7.5, boosted by the full moon's solunar pull. The major feeding period from 11:41 to 13:41 lines up with the second high tide, and the minor window around dawn could produce action despite the early-hour low at 06:40. Pressure is rising slowly from 1015 to 1018 millibars, a classic recipe for improving activity through the day. For anglers, the trade-off is that the sea breeze will pick up slightly by afternoon, but with gusts staying under 15 knots through evening, it's manageable. Surfing at 6.7 is decent but not excellent. The swell arrives from the south-southeast at 0.8 meters on a short 4.4-second period, so expect soft, crumbly waves best suited to a log or a mid-length. The calmest stretch of water comes around 14:00 when wave heights dip to 0.78 meters, but that also means less push. The full moon's higher tidal swings will expose more of the beach at low tide, so plan your session around the incoming tide after 13:14 for a little more shape. Sailing, boating, and kayaking all land in the mediocre range—5.3, 6.1, and 5.8 respectively. The light wind is fine for a leisurely paddle or a drift-fishing trip, but there's not enough pressure for a satisfying sail. The ocean current is ripping northeast at 2.2 meters per second, so kayakers need to watch their drift on the ebb. Wildlife viewing at 6.6 is decent but not exceptional; the high chlorophyll reading of 3.14 mg/m³ often correlates with bait, but without direct observations, don't bank on a show. Looking ahead, Friday stays similarly calm with waves dropping to 0.6-0.8 meters and even lighter swell, but a building breeze through the weekend will chop things up. By Sunday, winds could gust over 20 knots and rain chances climb past 30%, so today and tomorrow are your best windows for clean conditions before the pattern turns. If you're diving, get in the water around midday, when the tide is high but the sea is at its flattest.