Good Harbor Beach — Sea temperature now
Iconic North-Shore family beach.
Mild water with a light chop and a light breeze — comfortable conditions for most swimmers.
Location
Good Harbor Beach on the map, with nearby beaches and live sea temperatures.
7-day forecast
Water, air, waves, wind and UV outlook for the week ahead.
Monthly sea temperature averages
Typical year-round water temperature, based on regional climatology.
Best time to swim in Good Harbor Beach
The sea in Good Harbor Beach peaks in August, when the water averages around 20°C.
The main swimming season runs from August, when surface temperatures stay comfortable for extended sessions.
On average, 1 month a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
Shoulder months like July and September are noticeably cooler but often quieter, with fewer crowds and steadier weather.
Outside peak season the water drops toward 8°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable.
The coldest month is typically February at around 3°C, when cold-water swimmers dominate the coast.
Good Harbor Beach sea temperature history
Long-term climatology for Good Harbor Beach shows an annual mean sea temperature of 11°C, ranging from 3°C in winter to 20°C at the summer peak.
The seasonal swing is roughly 17°C between the coldest and warmest month — a useful yardstick when comparing years or checking whether the current sea is running above or below average.
Recent decades have trended slightly warmer at Good Harbor Beach, in line with regional sea-surface temperature records for the wider basin.
Monthly averages below are drawn from multi-decadal climatology and are updated as new observations arrive.
Good Harbor Beach sea temperature: frequently asked questions
What is the warmest month to swim in Good Harbor Beach?
August is the warmest month in Good Harbor Beach, when the sea averages about 20°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Good Harbor Beach?
The coldest month in Good Harbor Beach is typically February, when the water averages around 3°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Good Harbor Beach without a wetsuit?
The main swimming season in Good Harbor Beach runs from August — about 1 month a year when the sea sits above 20°C, the level most swimmers describe as pleasant without a wetsuit.
Do I need a wetsuit in Good Harbor Beach?
Outside peak summer the water in Good Harbor Beach drops toward 8°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable. In peak months most swimmers go without.
What is the average sea temperature in Good Harbor Beach?
The long-term annual mean sea temperature in Good Harbor Beach is about 11°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Good Harbor Beach?
The live reading at the top of this page shows the current sea temperature in Good Harbor Beach, updated hourly from marine buoy and satellite data. The 7-day forecast covers water, air, waves, wind and UV for the week ahead.
Year-round sea temperature
Best swim months: Aug
| Month | Sea | Comfort |
|---|---|---|
| Jan | 4°C | Cold |
| Feb | 3°C | Cold |
| Mar | 4°C | Cold |
| Apr | 6°C | Cold |
| May | 10°C | Cold |
| Jun | 15°C | Bracing |
| Jul | 19°C | Pleasant |
| Aug ⭐ | 20°C | Pleasant |
| Sep | 18°C | Pleasant |
| Oct | 14°C | Bracing |
| Nov | 10°C | Cold |
| Dec | 6°C | Cold |