SeasonMapNantucket weather in August
United States
August in Nantucket: warm, a little rain, with muggy air — one of the best months to visit.
#1 of 12 months in Nantucket · #378 of 1383 destinations to visit in August · comfort 87/100 (tier A)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Nantucket in August
Other months in Nantucket
Nantucket's forum rates July for warm, sunny days, with one recurring caveat worth knowing before booking a beach-heavy trip: the ocean itself stays genuinely chilly until August catches up, so swimming is more bracing than the air temperature would suggest. Regulars who want both warm water and warm air tend to point toward September instead.
Add your own note from Nantucket's card on the map.
Nantucket climate normals — August
| Daytime high | 25°C / 77°F | 🌤 warm |
|---|---|---|
| Nighttime low | 18°C / 65°F | |
| Feels like (high) | 27°C / 81°F | |
| Sea temperature | 20°C / 68°F | 🌊 fresh |
| Rainfall | 49 mm / 1.9 in | 🌦 some rain |
| Rainy days | 6 days | |
| Humidity | 88% | 💦 very humid |
| Dew point | 19°C / 65°F | |
| Sunshine | 10.9 h/day | |
| Daylight | 13.8 h | |
| Wind | 27 km/h / 17 mph | |
| Air quality (US AQI) | 61 | 🙂 moderate |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Nantucket in August
How busy the place itself is — school and mass holidays, the months an editor tagged, and how sought-after the weather makes them. Never part of the comfort score.
Peak crowdsHigh summer, Summer break in United States, school holidays in 2 of the markets that fill it(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Nantucket's weather
Ranked by this destination's own climate comfort score across the year — a different thing from how busy it gets (see Crowds above).
Best weatherNantucket's weather peaks June–August.
Best weatherFair weatherToughest weather
What's on in Nantucket in August
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Hazard
Tick season
1 Apr – 31 Oct · usuallyInsect seasonThe island's deer ticks carry Lyme, babesiosis and tularemia at rates among the highest anywhere, and the moors and bike-path verges are where they wait. Long trousers, and a check at the end of every day. Source ↗
- Season
High summer
1 Jul – 31 AugSchool holidaysCrowdedBook earlyPopulation multiplies by five, the car ferry is booked out months ahead and dinner needs a reservation two weeks early. Bring a bike instead of a car and the island works. Source ↗
- Season
Sea warm enough to swim
15 Jul – 20 Sep · usuallyThe island sits far enough offshore that the water lags the air by a month. The harbour beaches on the sound side are always several degrees warmer than the south shore. Source ↗
Nearby, and something's on
Within 300 km of Nantucket — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Nantucket?
Nantucket in August — FAQ
- Is August a good time to visit Nantucket?
- August in Nantucket: warm, a little rain, with muggy air — one of the best months to visit. It ranks #1 of 12 months for Nantucket on SeasonMap's comfort score (87/100).
- What is the weather like in Nantucket in August?
- In August, Nantucket averages a daily high of 25.1°C and a low of 18.2°C, with about 48.6 mm of rain over roughly 5.7 rainy days.
- What is the air quality in Nantucket in August?
- Nantucket has a mean US Air Quality Index of about 61 in August.
Other months in Nantucket
Compare Nantucket in August
Warmer or cooler than Nantucket in August
Similar destinations in North America — August
Within 300 km: Newport's Newport Jazz Festival on 31 Jul – 2 Aug, and Boston's Whales on Stellwagen Bank around 15 Apr – 20 Oct.