Martha's Vineyard Weather by Month: Complete Climate Guide (2026)

Martha's Vineyard sits 7 miles off the southern coast of Cape Cod in the Atlantic Ocean, and that water makes all the difference. The island's maritime climate keeps summers cooler and winters milder than mainland Massachusetts — typically 8–12°F warmer in winter and 5–8°F cooler in summer than Boston or Providence. Annual rainfall averages 47.7 inches, spread fairly evenly across all 12 months, and snowfall runs about 25 inches per year — significant, but nothing like inland New England.

What you get is a genuinely four-season island with distinct personalities in each season. Summer is warm and breezy. Fall is crisp and clear. Winter is wild and raw. Spring comes late but rewards patience. This guide gives you the full picture — real numbers, month by month, so you can plan with confidence.

Already know when you're going? Jump to the best time to visit guide for crowd and price context alongside the weather.

Monthly Climate Data: January–June

The table below covers the first half of the year. Columns show average high and low temperatures (°F), ocean surface temperature (°F), typical rain days per month, snow days, daily sunshine hours, average afternoon humidity (%), average wind speed (mph), recommended clothing, and a one-line summary.

Monthly Climate Data: July–December

The second half of the year brings summer's peak warmth, the clearest skies of the year in September and October, and then the slow return of winter. Ocean temperatures peak in August and hold warmth well into September.

Ocean Temperature on Martha's Vineyard

Martha's Vineyard's ocean temperatures tell a different story than you might expect. The island sits at the boundary between colder Gulf of Maine waters and the warmer offshore flow influenced by the Gulf Stream. That interaction creates a thermal buffer — the water never gets as cold as Maine, but it also never reaches the bath-like warmth of the Carolina coast.

The swimming season runs July through September only. Ocean temps reach 68°F in July and peak at 70°F in August — warm enough for comfortable swimming, though still noticeably cooler than a heated pool. September holds at 67°F, which most swimmers find perfectly acceptable. By October, the water drops to 62°F — brave souls only. November's 55°F is wetsuit territory.

One counterintuitive pattern: September ocean water is warmer than May ocean water by 14°F (67°F vs 53°F). This is thermal lag — the ocean takes months to absorb summer heat and releases it slowly into fall. If swimming is a priority, September is a far better month than June despite having similar air temperatures.

June is the foggiest month on the island for exactly this reason. Warm, humid air moving off the warmer land masses meets the still-cool ocean water, and the temperature differential creates persistent sea fog — sometimes burning off by midday, sometimes hanging all day. It's atmospheric and beautiful, but plan around it.

For more on timing your beach visit, see the Martha's Vineyard beach guide.

Snow, Rain, and Storms

Martha's Vineyard averages 25.3 inches of snow per year — enough to be significant, but the maritime climate means most winter precipitation falls as rain or mixed precipitation rather than clean snow. True accumulating snowstorms are memorable events rather than weekly occurrences.

Nor'easters hit the island one to three times per winter, typically between November and March. These storms arrive from the northeast with howling winds, heavy precipitation, and rough surf. They can dump 12–18 inches of snow or deliver damaging rain and coastal flooding depending on the storm track. The most severe nor'easters cause ferry cancellations and road closures. The February 2026 blizzard dropped over 18 inches on the island — one of the heaviest single-storm totals in recent years.

The island's hurricane exposure is real. Hurricane Bob in 1991 remains the benchmark storm — 100+ mph gusts, significant structural damage, and a permanent place in island memory. The off-season guide covers storm preparedness for winter visitors.

Looking at rainfall across the year, July is the driest month with only 7 days of measurable rain — one reason it's so popular for vacations. December is the wettest, with 12 rain days on average. The difference between the driest and wettest months is relatively small compared to continental climates, which reflects the maritime pattern of year-round moisture.

Total annual rainfall of 47.7 inches is distributed fairly evenly, so no month is truly dry. Bring a light rain layer any time of year.

Wind and Sunshine

Wind is a constant presence on Martha's Vineyard. The island's exposed position in the Atlantic means the wind rarely stops entirely — it's part of what makes summer afternoons so refreshing and winter days so biting.

March is traditionally the windiest month on the island, with persistent westerly and northwesterly winds and frequent gusts. January and February record the highest wind speeds in actual measurements (both averaging 17 mph), but March's wind feels relentless because it combines with the transition from winter to spring. August is the calmest month, when the Bermuda High pressure system settles over the Atlantic and delivers stable, gentle southwest breezes — ideal sailing and beach conditions.

Sunshine follows a satisfying pattern. June and July both average 9 hours of sunshine per day — the island's peak. Long June days (nearly 15 hours of daylight around the solstice) mean even foggy mornings often yield beautiful afternoons. September and October deliver the clearest skies, with the highest sunshine ratio (percentage of possible daylight hours that are actually sunny) of any months — around 60–61%. This is why fall visitors so often become the island's most devoted repeat visitors.

Daylight extremes are significant at this latitude:

• Summer solstice (late June): 15 hours and 10 minutes of daylight — evening light until nearly 9pm
• Winter solstice (late December): 9 hours and 5 minutes of daylight — dark by 4:15pm

For June visits, the long light is magical. For July and August, plan beach time in the afternoon when sea breezes peak. September and October offer that crystalline fall light that photographers chase.

Season-by-Season Overview

Peak Season: Late June through Labor Day

This is the island at full throttle. Every restaurant is open, every beach is staffed, ferries run at maximum frequency, and prices are at their highest. Air temperatures are reliably warm (highs in the mid-70s to low 80s), the ocean is swimmable, and the light is extraordinary. The tradeoff is crowds — beaches fill by 10am on weekends, restaurants require advance reservations, and ferry standby lines can stretch for hours. Book everything as early as possible. See the spring guide for advance planning tips that apply to summer bookings too.

Shoulder Season: May–June and September–October

The island's best-kept secret. Weather in May and early June is mild and green, with wildflowers blooming and restaurants running full menus without the summer crush. September and October bring arguably the finest weather of the year — clear skies, warm ocean (September), fall foliage (October), and hotel prices that drop 30–50% from August peaks. Some businesses begin closing in mid-October, so check hours before you go. The September guide and October fall foliage guide have full details on what's open and what to do.

Off-Season: November through April

The real island emerges. Year-round residents make up nearly the entire population, most summer businesses are shuttered, and the landscape is raw and beautiful. Accommodation prices drop dramatically, and the few restaurants that stay open are excellent. Winter hiking, birding, and storm-watching from the cliffs are genuinely rewarding. The risks are real too: weather can change fast, ferry service may be disrupted, and you need to plan meals around limited hours. The winter off-season guide covers everything you need to know.

Quick Reference: Martha's Vineyard Climate Facts

• Annual rainfall: 47.7 inches, distributed fairly evenly year-round
• Annual snowfall: 25.3 inches average; most years 15–35 inches depending on nor'easters
• Maritime temperature moderation: 8–12°F warmer than mainland Massachusetts in winter; 5–8°F cooler in summer
• Warmest months (air): July and August — both average 80°F high / 64°F low
• Coldest month (air): January — average 40°F high / 26°F low
• Warmest ocean: August at 70°F
• Coldest ocean: February at 38°F
• Swimming season: July, August, September only (68–70°F)
• Foggiest month: June (warm air meets cold ocean)
• Driest month: July (7 rain days)
• Wettest month: December (12 rain days)
• Windiest period: November through March (17 mph average)
• Calmest month: August (12 mph average)
• Sunniest months: June and July (9 hours/day)
• Clearest skies: September and October (60–61% sunshine ratio)
• Max daylight: 15h 10m (summer solstice)
• Min daylight: 9h 5m (winter solstice)
• Nor'easters per winter: 1–3 on average
• Last major blizzard: February 2026, 18+ inches

What to Pack by Season

For the full packing breakdown, see the Martha's Vineyard packing list. Here's the short version:

Summer (Late June–Labor Day)

• Swimsuit(s) — you'll use them daily
• Shorts, t-shirts, and sundresses for days
• A light sweater or hoodie for evenings — the ocean breeze drops temperatures noticeably after sunset
• Comfortable walking shoes and sandals
• Sunscreen and a hat — UV index is high on the water
• A packable rain layer — brief afternoon thunderstorms are possible in July and August

Shoulder Season (May–June and September–October)

• Layering is the core strategy — temperatures can swing 25°F from morning to afternoon
• A light-to-medium jacket for evenings and cooler days
• Comfortable, versatile shoes that can handle damp conditions
• In June: bring a light rain layer and be ready for fog that doesn't burn off
• In October: add a fleece and consider waterproof boots for extended outdoor time

Winter (November–April)

• A serious insulated coat — the wind makes temperatures feel 10–15°F colder than the thermometer reads
• Waterproof, insulated boots — rain and mud are constants
• Warm hat, gloves, and a scarf — not optional
• Multiple base layers and fleece mid-layers
• Wind-resistant outer layer for beach and cliff walks