ERA5 almanac comparison — 8 years of real data
Martha's Vineyard vs Sea Island: weather in May
Sea Island is the clear winner for sun in May: 36% of days historically clear versus just 3% in Martha's Vineyard — a 33-point gap across 8 years of ERA5 data. This isn't close.
Martha's Vineyard
MA
- Clear days, May
- 3%
- Sample size
- n=248 days
- Avg high
- 62°F
- Early May (1st–15th)
- 1%
- Late May (16th–end)
- 4%
- Rain frequency
- 35% of days
Sea Island
GA
- Clear days, May
- 36%
- Sample size
- n=248 days
- Avg high
- 81°F
- Early May (1st–15th)
- 41%
- Late May (16th–end)
- 31%
- Rain frequency
- 36% of days
Frequently asked
Is Martha's Vineyard or Sea Island warmer in May?
Sea Island runs warmer by day in May. Martha's Vineyard averages highs of 62°F (highs n=248 days); Sea Island averages highs of 81°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 May?
Days with measurable rain: Martha's Vineyard 35%, Sea Island 36% (n=248 and n=248 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in May, Martha's Vineyard or Sea Island?
Sea Island is the clear winner for sun in May: 36% of days historically clear versus just 3% in Martha's Vineyard — a 33-point gap across 8 years of ERA5 data. 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.