ERA5 almanac comparison — 8 years of real data
Martha's Vineyard vs Sea Island: weather in August
Martha's Vineyard is the clear winner for sun in August: 46% of days historically clear versus just 7% in Sea Island — a 39-point gap across 8 years of ERA5 data. Sea Island also sees measurably more rain than Martha's Vineyard this month (66% vs 35% of days). This isn't close.
Martha's Vineyard
MA
- Clear days, August
- 46%
- Sample size
- n=248 days
- Avg high
- 77°F
- Early August (1st–15th)
- 48%
- Late August (16th–end)
- 45%
- Rain frequency
- 35% of days
Sea Island
GA
- Clear days, August
- 7%
- Sample size
- n=248 days
- Avg high
- 85°F
- Early August (1st–15th)
- 6%
- Late August (16th–end)
- 8%
- Rain frequency
- 66% of days
Frequently asked
Is Martha's Vineyard or Sea Island warmer in August?
Sea Island runs warmer by day in August. Martha's Vineyard averages highs of 77°F (highs n=248 days); Sea Island averages highs of 85°F (highs n=248 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Martha's Vineyard or Sea Island in August?
Sea Island is measurably wetter than Martha's Vineyard. Days with measurable rain: Martha's Vineyard 35%, Sea Island 66% (n=248 and n=248 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in August, Martha's Vineyard or Sea Island?
Martha's Vineyard is the clear winner for sun in August: 46% of days historically clear versus just 7% in Sea Island — a 39-point gap across 8 years of ERA5 data. Sea Island also sees measurably more rain than Martha's Vineyard this month (66% vs 35% of days). This isn't close.
Compare Martha's Vineyard vs Sea Island in another month
All percentages are historical averages from the ERA5 reanalysis via Open-Meteo, 8 full years (2018–2025). “Clear” means avg high ≥ 72 °F, precipitation < 1 mm, and a non-precipitation weather code. This is history, not a forecast. The live forecast for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.