ERA5 almanac comparison — 8 years of real data
Martha's Vineyard vs Sea Island: weather in March
Sea Island edges out Martha's Vineyard for sun in March: 15% clear historically versus 0% (8-year ERA5 average, a 15-point gap). Both are viable — Sea Island is the safer bet.
What you are reading: 8-year historical averages, not a forecast.
Either destination can still surprise you this specific March. For this
week’s actual forecast, each destination links to its live page below.
Martha's Vineyard
MA
- Clear days, March
- 0%
- Sample size
- n=248 days
- Avg high
- 46°F
- Early March (1st–15th)
- 0%
- Late March (16th–end)
- 0%
- Rain frequency
- 36% of days
Sea Island
GA
- Clear days, March
- 15%
- Sample size
- n=248 days
- Avg high
- 69°F
- Early March (1st–15th)
- 12%
- Late March (16th–end)
- 17%
- Rain frequency
- 29% of days
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 7-day outlook for any destination is on its own page and may differ from the long-run average. Data from Open-Meteo.