Sea water temperature · United States
Water temperature in Chatham, Cape Cod today
How warm is the sea in Chatham, Cape Cod today? The water temperature below is loaded live every time you open the page, compared with the normal for October, with the wetsuit it calls for and the waves.
The water right now
The sea at Chatham, Cape Cod is 14.4 °C (58 °F) right now. That is about the October average (14.0 °C).
As of 2026-10-16 14:45 UTC (Open-Meteo Marine snapshot). Updating live…
Water temperature and waves, next days
| Day | Water | Waves | Period | Wetsuit |
|---|---|---|---|---|
| Fri 16 Oct | 14.3–14.5 °C | 1.4 m | 5 s | 4/3–5 mm wetsuit |
| Sat 17 Oct | 14.0–14.3 °C | 1.5 m | 5 s | 4/3–5 mm wetsuit |
| Sun 18 Oct | 13.8–14.0 °C | 1.4 m | 5 s | 4/3–5 mm wetsuit |
| Mon 19 Oct | 13.7–13.8 °C | 2.6 m | 8 s | 4/3–5 mm wetsuit |
| Tue 20 Oct | 13.7–13.8 °C | 2.7 m | 8 s | 4/3–5 mm wetsuit |
| Wed 21 Oct | 13.7–13.7 °C | 2.7 m | 7 s | 4/3–5 mm wetsuit |
| Thu 22 Oct | 13.6–13.6 °C | 2.6 m | 7 s | 4/3–5 mm wetsuit |
Days in local time (America/New_York). Water: lowest–highest sea surface temperature of the day; waves: highest significant wave height and its period.
Average water temperature in Chatham, Cape Cod by month
Monthly averages 1991–2020 from NOAA OISST v2.1 (0.25° satellite and in-situ analysis) at the nearest ocean cell; this month in bold.
What wetsuit for this water?
| Water | Wetsuit | |
|---|---|---|
| 24 °C+ | No wetsuit | swimwear is enough |
| 21–24 °C | Shorty or lycra | warm, a thin layer for long sessions |
| 17–21 °C | 3/2 mm wetsuit | cool: a full suit for swimming or surfing |
| 13–17 °C | 4/3–5 mm wetsuit | cold: a thick full suit |
| < 13 °C | 5 mm+ and boots | very cold: thick suit, boots, maybe gloves and hood |
A rule of thumb for swimming and surfing; wind, sun and how long you stay in change it.
Sea temperature map around Chatham, Cape Cod
Satellite sea surface temperature (GHRSST MUR, 1 km, daily): warm water red, cold water blue. Tap the sea for the value.
More for the sea at Chatham, Cape Cod
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The sea at Chatham, Cape Cod through the year
The water at Chatham, Cape Cod is warmest in August (19.4 °C on average) and coldest in March (4.7 °C). In October it averages 14.0 °C: 4/3–5 mm wetsuit (cold: a thick full suit). The temperatures are for the sea just off the beach (41.75°, -69.75°).
Questions
- What is the water temperature in Chatham, Cape Cod today?
- On 16 October 2026 the sea surface at Chatham, Cape Cod was 14.4 °C (58 °F). The box at the top of the page loads the current value from Open-Meteo Marine every time you open it, with the forecast for the next days.
- How warm is the sea in Chatham, Cape Cod in October?
- The 1991–2020 average for October is 14.0 °C. The warmest month is August (19.4 °C), the coldest March (4.7 °C).
- Do I need a wetsuit in Chatham, Cape Cod?
- At the October average of 14.0 °C: 4/3–5 mm wetsuit (cold: a thick full suit). Above 24 °C most people swim without one; below 17 °C a full suit of 4 mm or more is the norm.
- Why can the water at the beach feel different?
- These are model and satellite values for the sea surface a little offshore. In shallow bays the water can be warmer on sunny days, and offshore winds can bring up colder water from below (upwelling) within hours.
Water temperature nearby
Provincetown · Nantucket · Newport, Rhode Island · Ogunquit · Montauk · Bar Harbor
How this page works
The temperature now and the next days are the sea surface temperature from the Open-Meteo Marine API (ocean and wave models of Copernicus Marine, Météo-France and ECMWF) at the sea point off Chatham, Cape Cod, fetched in your browser; waves are the significant wave height and peak period from the same API. The monthly averages are NOAA OISST v2.1 1991–2020 long-term means. The map is the sea surface temperature layer (NASA JPL GHRSST MUR via NASA GIBS).