Marine forecast
Boston Harbor, MA
- current wind
- 8 kt WNW
- Gusts
- 12 kt
- Seas
- 1.0 ft
- Period
- 8 sec
- Air
- 74°F
Observed Wed 12:30 PM | ANZ230
- Gusts now
- 12 kt
- Seas now
- 1.0 ft · 8 sec
- Air
- 74°F
- 72-hr peak
- 27 kt
- Peak seas
- 2 ft
In brief
At 12:30 pm EDT on Oct 14, 2026, NDBC station CSIM3 (Castle Island (NOS) 8444069, 5 miles away) measured wind from the WNW at 8 kt, gusting to 12 kt; buoy 44090 measured seas of 1.0 ft. The NWS forecast for Boston Harbor, MA issued at 10:04 am EDT on Oct 14, 2026 reads, for this afternoon: “W winds 5 to 10 kt with gusts up to 20 kt. Waves around 2 ft.” A Small Craft Advisory is in effect until Thu 2:00 PM.
Source: National Weather Service Boston/Norton MA forecast; NDBC observations
Wind forecast · ktPeak 27 kt
Seas forecast · ftPeak 2 ft
Marine advisory
Small Craft Advisory in effect for Boston Harbor until Thu 2:00 PM.
Full text of this small craft advisory
* WHAT...For the Small Craft Advisory, northwest winds 10 to 20 kt with gusts up to 25 kt and waves 1 to 2 feet expected. For the Gale Watch, west winds 15 to 25 kt with gusts up to 35 kt and waves around 2 feet possible. * WHERE...Boston Harbor. * WHEN...For the Small Craft Advisory, from 8 PM this evening to 2 PM EDT Thursday. For the Gale Watch, from Friday evening through Saturday evening. * IMPACTS...Strong winds can cause hazardous waves which could capsize or damage vessels and reduce visibility.
Gale Watch in effect for Boston Harbor until Sat 8:00 PM.
Full text of this gale watch
* WHAT...For the Small Craft Advisory, northwest winds 10 to 20 kt with gusts up to 25 kt and waves 1 to 2 feet expected. For the Gale Watch, west winds 15 to 25 kt with gusts up to 35 kt and waves around 2 feet possible. * WHERE...Boston Harbor. * WHEN...For the Small Craft Advisory, from 8 PM this evening to 2 PM EDT Thursday. For the Gale Watch, from Friday evening through Saturday evening. * IMPACTS...Strong winds can cause hazardous waves which could capsize or damage vessels and reduce visibility.
NWS marine forecast
| Period | Forecast |
|---|---|
| This Afternoon | W winds 5 to 10 kt with gusts up to 20 kt. Waves around 2 ft. A slight chance of showers. |
| Tonight | NW winds 10 to 15 kt with gusts up to 25 kt. Waves around 2 ft. |
| Thu | NW winds 15 to 20 kt, becoming N 5 to 10 kt in the afternoon. Waves around 2 ft in the morning, then 1 foot or less. |
| Thu Night | E winds around 5 kt, becoming S after midnight. Waves 1 foot or less. A chance of showers after midnight. |
| Fri | S winds 10 to 15 kt with gusts up to 25 kt. Waves 2 to 3 ft. Showers. |
| Fri Night | SW winds 15 to 20 kt, becoming W 20 to 25 kt after midnight. Gusts up to 30 kt. Waves around 2 ft. Showers. |
| Sat Through Sun Night | SW winds 20 to 25 kt with gusts up to 30 kt. Waves around 2 ft. 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. |
Issued Wed 10:04 AM by Boston/Norton MA (product CWFBOX).
Recent buoy conditions
| Time | Wind | Gust | Seas | Water |
|---|---|---|---|---|
| Wed 12:30 PM | 8 kt WNW | 12 kt | — | — |
| Wed 11:54 AM | 6 kt W | 11 kt | — | — |
| Wed 10:54 AM | 11 kt W | 19 kt | — | — |
| Wed 9:54 AM | 5 kt W | 9 kt | — | — |
| Wed 5:00 AM | — | — | — | — |
| Wed 4:54 AM | — | — | — | — |
| Wed 3:54 AM | — | — | — | — |
| Tue 11:18 PM | 4 kt ENE | 5 kt | — | — |
| Tue 10:54 PM | 2 kt NNE | 2 kt | — | — |
| Tue 9:54 PM | 0 kt | 1 kt | — | — |
| Tue 8:54 PM | 0 kt | 2 kt | — | — |
| Tue 7:54 PM | 3 kt S | 4 kt | — | — |
Observed Wed 12:30 PM at NDBC buoy CSIM3 (Castle Island (NOS) 8444069), 4.9 miles away. Seas from buoy 44090 (Cape Cod Bay, MA (221)), 44.4 miles away, at Wed 12:00 PM.
Frequently asked questions
What is the marine forecast for Boston Harbor today?
This Afternoon: W winds 5 to 10 kt with gusts up to 20 kt. Waves around 2 ft. A slight chance of showers.
Is there a small craft advisory for Boston Harbor?
Yes — small craft advisory, gale watch in effect until Thu 2:00 PM.
How high are the waves at Boston Harbor right now?
Seas are running 1.0 ft at a 8-second period, measured at NDBC buoy CSIM3 Wed 12:30 PM, 4.9 miles from this zone. The forecast peaks at 2.0 ft Wed 1 PM.
What do the wind speeds in knots mean?
One knot is 1.15 mph. The National Weather Service issues a small craft advisory for sustained winds of roughly 22–33 knots or hazardous seas, a gale warning at 34–47 knots, and a storm warning at 48 knots and above. Exact advisory thresholds vary by forecast office and by water body — a bay reaches dangerous chop at a lower wind speed than open ocean.
Where does this forecast come from?
The forecast text is the National Weather Service's own marine bulletin for zone ANZ230, issued by Boston/Norton MA, reproduced in full. The wind and seas charts are drawn from the NWS gridded forecast for a point inside the zone. Observations come from the nearest reporting NDBC buoy. We are not affiliated with NOAA or the National Weather Service.
Forecast: NOAA/NWS product CWFBOX, issued Wed 10:04 AM. Observations: NOAA National Data Buoy Center station CSIM3, read Wed 12:30 PM. Retrieved Oct 14, 1:09 PM. Conditions offshore change faster than any page can be rebuilt, so check the current NWS bulletin and your own instruments before going out.