Rhode Island · Connecticut boating conditions
Block Island Sound marine forecast
A cross-sound view of conditions around Block Island, Watch Hill, Mystic, and New London.
For the rest of today: Block Island Sound S 10–15 kt, gusts 20, seas 2–3 ft. Best day this week: Mon, Nov 9. Mon, Nov 9 is the mildest day in the forecast. It is still Nope on at least one period.
Forecast checked Thu, Nov 5, 2026, 3:04 AM EST · National Weather Service coastal waters forecast issued 1:03 AM EST · harbor briefings updated 3:04 AM EST · water temperature updated 3:00 AM EST
Right now
Block Island Sound conditions today
Each flag is that harbor's live call. Zone labels use the coastal waters forecast for the rest of today.
- Block Island
- Buzzards BaySW 10 kt gust 10
One harbor briefing is unavailable.
NWS coastal waters forecast
Block Island Sound forecast by zone
Each period is scored with the same limits as the harbor pages: 15 kt wind, 20 kt gusts, 2.5 ft seas. Thunderstorms or reduced visibility turn a period to Caution.
The sound itself, between the island and the mainland
No advisoryOfficial NWS text for each zone
Block Island Sound (ANZ237)
Rest Of Tonight: SW winds around 10 kt. Seas around 2 ft. Wave Detail: SW 2 ft at 4 seconds and SE 1 foot at 8 seconds. Patchy fog. Vsby 1 to 3 NM.
Thu: S winds 10 to 15 kt with gusts up to 20 kt. Seas 2 to 3 ft. Wave Detail: S 3 ft at 5 seconds and SE 2 ft at 9 seconds. Patchy fog in the morning with vsby 1 NM or less.
Thu Night: SW winds around 15 kt with gusts up to 20 kt. Seas 3 to 4 ft. Wave Detail: SW 3 ft at 5 seconds and SE 2 ft at 9 seconds. A chance of rain in the evening, then rain after midnight. Patchy fog after midnight with vsby 1 to 3 NM.
Fri: SW winds 10 to 15 kt. Gusts up to 20 kt in the morning. Seas 2 to 4 ft. Wave Detail: SW 3 ft at 5 seconds and SE 3 ft at 9 seconds. Patchy fog. Rain with a chance of tstms. Vsby 1 to 3 NM.
Fri Night: SW winds 5 to 10 kt, becoming W after midnight. Seas 3 to 4 ft. Wave Detail: S 4 ft at 7 seconds. Patchy fog. Rain. A chance of tstms in the evening. Vsby 1 to 3 NM.
Sat: NW winds 5 to 10 kt, becoming W 10 to 15 kt in the afternoon. Seas 3 to 4 ft. Wave Detail: S 4 ft at 7 seconds.
Sat Night: W winds 10 to 15 kt, increasing to 15 to 20 kt after midnight. Gusts up to 25 kt. Seas 4 to 6 ft. A chance of rain.
Sun: W winds 15 to 20 kt with gusts up to 25 kt. Seas 4 to 6 ft.
Sun Night and Mon: W winds 15 to 20 kt with gusts up to 30 kt. Seas 3 to 5 ft.
Mon Night: NW winds 15 to 20 kt with gusts up to 25 kt. Seas 2 to 4 ft. Winds and seas higher in and near tstms. Seas are reported as significant wave height, which is the average of the highest third of the waves. Individual wave heights may be more than twice the significant wave height.
Five-day trend
Wind and seas across Block Island Sound
Day and night bars for each zone, in the same wind and seas chart style as a harbor page. A missing bar is a period the forecast did not quantify.
Block Island Sound
Dashed limit on the harbor pages: 15 kt. Bars are the top of the forecast range.
Dashed limit on the harbor pages: 2.5 ft. Bars are the top of the forecast range.
Harbor-level briefings
Compare conditions around Block Island Sound
Island and Rhode Island shore
Exposed island water and the eastern side of the sound.
An offshore island with primary boating access at Great Salt Pond and Old Harbor.
10 ktseas 2 ft60°F water
Conditions are Caution now, and seas exceed your 2.5 ft limit around 7 AM; plan to be back before then.
A coastal destination at the entrance to Little Narragansett Bay, near Napatree Point and Fishers Island Sound.
6 ktseas 2 ft60°F water
Conditions are Caution now, and seas exceed your 2.5 ft limit around 7 AM; plan to be back before then.
A marina destination inside Point Judith Pond, reached through the busy breachway at Galilee and sheltered from the open Rhode Island coast.
10 ktseas 2 ft0°F water
Conditions are Caution now and remain evaluated through 7:04 AM.
Connecticut approaches
Harbors feeding the western and northern side of the sound.
A historic Mystic River destination reached from Fishers Island Sound through a narrow, well-traveled channel.
7 ktseas 2 ft60°F water
Conditions are Caution now, and seas exceed your 2.5 ft limit around 7 AM; plan to be back before then.
A deep harbor at the Thames River mouth with naval, ferry, and commercial traffic.
6 ktseas 0 ft60°F water
Wave-height coverage is unavailable right now, so this outing cannot be evaluated safely.
Part of this briefing is missing, so the call is incomplete.
Open marine conditions →Tide charts
Tide charts around Block Island Sound
- High tide 4:21 AM · 4 ft · Low tide 10:49 AM · 0.34 ft · High tide 4:47 PM · 3.55 ft · Low tide 10:47 PM · 0.23 ft59.2°Fwater
- High tide 6:03 AM · 3.02 ft · Low tide 12:37 PM · 0.32 ft · High tide 6:24 PM · 2.55 ft59.2°Fwater
The regional picture
One body of water. More than one kind of boat day.
Block Island Sound connects exposed island water, Rhode Island’s south shore, and the eastern Connecticut approaches. Conditions at the island can be a very different proposition from a protected river or harbor only a short run away.
Compare the sound-wide setup with the latest destination briefings below. The goal is not to flatten the area into one number - it is to make the differences easier to see before you leave the dock.
Before leaving the dock
Three useful checks for Block Island Sound
- Give the Block Island briefing extra weight for exposed crossings, not just the calmer departure harbor.
- Check tide and current timing at the eastern approaches and harbor entrances.
- Watch for advisories that cover the sound even when the marina itself feels sheltered.
What this regional guide can - and cannot - do
These pages make it easier to compare the latest available forecast and observation inputs around Block Island Sound. They are planning aids, not navigation or safety guarantees. Check the official coastal waters forecast, current observations and notices, local conditions, and your own boat and crew before departure.
See how Boat or Nope builds each call