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Map of Harwich reef
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Boat entry

Harwich reef

Massachusetts, United States
Open Water suggested10 m (33 ft) depthBoat entry7mm or semi-dry + hood typical

Boat dive — see Entry & access.

Harwich reef at a glance

Harwich reef is a boat dive site in Massachusetts, United States with depths of up to 10.1 m (33 ft). Typically most favorable Jun · from 3 years of archive data. Recent reports put the water around 13°C (55°F). Check the latest conditions and entry details before you go.

Favorable window now· until 18:00 · sunset 17:42

Forecast for this hour · 15:00 · run 2 h ago
0.5 m (1.7 ft)waves — under a meter expected (waves — about two feet expected)

Tap a factor for its source and model point · Forecast 13°C · seasonal avg 16°C ( · Forecast 55°F · seasonal avg 61°F)

Dive windows this week

Lightest wind: Wed
Mon14:00–18:00 favorable

0.5 m waves · 12 kn wind (1.6 ft waves · 12 kn wind)

Tue8:00–18:00 favorable

0.7 m waves · 14 kn wind (2.1 ft waves · 14 kn wind)

Wed8:00–18:00 favorable

0.3 m waves · 6 kn wind (0.9 ft waves · 6 kn wind)

Thu8:00–18:00 favorable

0.4 m waves · 12 kn wind (1.3 ft waves · 12 kn wind)

Fri8:00–11:00 moderate, 11:00–18:00 favorable

0.5 m waves · 9 kn wind (1.6 ft waves · 9 kn wind)

Sat8:00–18:00 favorable

0.3 m waves · 11 kn wind (1.0 ft waves · 11 kn wind)

Sun8:00–18:00 favorable

0.3 m waves · 9 kn wind (0.9 ft waves · 9 kn wind)

Favorable windowModerate window— no window

Every forecast dive window each day, site-local time, from wave and wind forecasts. Numbers under each bar are daylight averages.

First light 6:36 · Sunrise 7:05 · Sunset 17:42 · some windows run past sunset

Source: Open-Meteo marine · model point 4.5 km from site · updated 26 Oct, 13:26 GMT-4

Forecast only — always assess conditions on site.

Compare this weekend’s windows near Harwich reef

Forecast · NOAA tide model

Tide & slack timing

Loading tide predictions

Recent diver reports

Dated firsthand observations from divers — not current conditions.

No diver reports for this site yet. — one dated observation helps every diver after you.

Dived here today — did the forecast match?

Best months, historically

What conditions have historically been typical at this site, month by month — not a forecast.

  1. January, 34% of days have historically been favorable, water has typically been 4°C (40°F), waves have typically been 1.4 m (4.6 ft), wind has typically been 23 knots
  2. February, 28% of days have historically been favorable, water has typically been 3°C (38°F), waves have typically been 1.4 m (4.6 ft), wind has typically been 24 knots
  3. March, 29% of days have historically been favorable, water has typically been 5°C (41°F), waves have typically been 1.5 m (4.8 ft), wind has typically been 24 knots
  4. April, 46% of days have historically been favorable, water has typically been 8°C (47°F), waves have typically been 1.2 m (3.9 ft), wind has typically been 21 knots
  5. May, 65% of days have historically been favorable, water has typically been 13°C (55°F), waves have typically been 1.1 m (3.4 ft), wind has typically been 19 knots
  6. June, 83% of days have historically been favorable, water has typically been 18°C (65°F), waves have typically been 0.9 m (2.8 ft), wind has typically been 17 knots, historically most favorable
  7. July, 83% of days have historically been favorable, water has typically been 23°C (74°F), waves have typically been 0.8 m (2.7 ft), wind has typically been 16 knots
  8. August, 82% of days have historically been favorable, water has typically been 24°C (75°F), waves have typically been 0.9 m (3.0 ft), wind has typically been 16 knots
  9. September, 72% of days have historically been favorable, water has typically been 20°C (69°F), waves have typically been 1.0 m (3.4 ft), wind has typically been 17 knots
  10. October, 53% of days have historically been favorable, water has typically been 16°C (61°F), waves have typically been 1.2 m (4.0 ft), wind has typically been 20 knots
  11. November, 38% of days have historically been favorable, water has typically been 11°C (51°F), waves have typically been 1.3 m (4.1 ft), wind has typically been 23 knots
  12. December, 38% of days have historically been favorable, water has typically been 6°C (43°F), waves have typically been 1.4 m (4.6 ft), wind has typically been 23 knots

June has typically had the largest share of favorable days here. Conditions vary year to year — this is historical context, not a forecast.

Based on 3 years of archive data. Bar height shows the share of days each month whose conditions have historically scored favorably.

Marine life recorded at this site

No recorded sightings data for this site yet. Species lists appear as GBIF records and diver reports accumulate.

Fills & rentals nearby

No dive shops mapped within 25 km (16 mi). Know one? Add it to the map.

Data updated July 2026

Site details

Artificial reef built from Concrete

reef

No hazards recorded for this site yet — that never means there are none. Ask a local operator before you dive.

Reviews

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