SeasonMapHyannis (Cape Cod) weather in May
United States
May in Hyannis: nice, rainy, with clean air — a great time to visit.
#5 of 12 months in Hyannis · #971 of 1383 destinations to visit in May · comfort 72/100 (tier B)
Updated September 2026 · climate normals from ERA5 reanalysis
Traveller notes on Hyannis in May
No notes yet. Open Hyannis on the map to add the first one.
Hyannis climate normals — May
| Daytime high | 18°C / 64°F | 😎 nice |
|---|---|---|
| Nighttime low | 9°C / 48°F | |
| Feels like (high) | 17°C / 63°F | |
| Sea temperature | 15°C / 58°F | 🥶 cold sea |
| Rainfall | 101 mm / 4 in | 🌧 rainy |
| Rainy days | 10 days | |
| Humidity | 80% | 💦 very humid |
| Dew point | 9°C / 47°F | |
| Sunshine | 9.9 h/day | |
| Daylight | 14.6 h | |
| Wind | 24 km/h / 15 mph | |
| Air quality (US AQI) | 44 | 🍃 good |
Monthly averages from ERA5 reanalysis. AQI is the mean US Air Quality Index for the month.
Crowds in Hyannis in May
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 crowdsIsland ferry high season, Figawi race weekend(estimated)
Peak crowdsBusyShoulder seasonQuiet
Best months for Hyannis'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).
Fair weatherHyannis's weather peaks June–August, best around July.
Best weatherFair weatherToughest weather
What's on in Hyannis in May
Recurring seasonal events, natural spectacles, closures and holidays — curated and sourced.
- Opening
Island ferry high season
20 May – 15 Oct · usuallySummer season opensCrowdedBook earlyHyannis is the mainland end of the Nantucket boats, and the summer timetable adds fast ferries and extra sailings from late May. Car spaces on the traditional boat are released months ahead and go the day they open. Source ↗
- Festival
Figawi race weekend
22–31 May · usuallyMajor festivalCrowdedBook earlySeveral hundred boats race out to Nantucket on the Saturday of Memorial Day weekend and party at both ends of it. It is the unofficial start of the Cape season and the first weekend rooms in Hyannis are hard to get. Source ↗
Nearby, and something's on
Within 300 km of Hyannis — a day trip or a short hop — with something on this month. Never part of the comfort score.
Where is Hyannis?
Hyannis in May — FAQ
- Is May a good time to visit Hyannis?
- May in Hyannis: nice, rainy, with clean air — a great time to visit. It ranks #5 of 12 months for Hyannis on SeasonMap's comfort score (72/100).
- What is the weather like in Hyannis in May?
- In May, Hyannis averages a daily high of 17.8°C and a low of 8.9°C, with about 101.4 mm of rain over roughly 10.4 rainy days.
- What is the air quality in Hyannis in May?
- Hyannis has a mean US Air Quality Index of about 44 in May.
Other months in Hyannis
Compare Hyannis in May
Warmer or cooler than Hyannis in May
Similar destinations in North America — May
Within 300 km: Nantucket's Daffodil Festival around 20 Apr – 2 May, and Boston's Whales on Stellwagen Bank around 15 Apr – 20 Oct.