ERA5 almanac comparison — 8 years of real data
Martha's Vineyard vs San Antonio: weather in December
San Antonio edges out Martha's Vineyard for sun in December: 17% clear historically versus 0% (8-year ERA5 average, a 17-point gap). Martha's Vineyard also sees measurably more rain than San Antonio this month (39% vs 21% of days). Both are viable — San Antonio is the safer bet.
Martha's Vineyard
MA
- Clear days, December
- 0%
- Sample size
- n=248 days
- Avg high
- 45°F
- Early December (1st–15th)
- 0%
- Late December (16th–end)
- 0%
- Rain frequency
- 39% of days
San Antonio
TX
- Clear days, December
- 17%
- Sample size
- n=248 days
- Avg high
- 68°F
- Early December (1st–15th)
- 20%
- Late December (16th–end)
- 14%
- Rain frequency
- 21% of days
Frequently asked
Is Martha's Vineyard or San Antonio warmer in December?
San Antonio runs warmer by day in December. Martha's Vineyard averages highs of 45°F (highs n=248 days); San Antonio averages highs of 68°F (highs n=248 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Martha's Vineyard or San Antonio in December?
Martha's Vineyard is measurably wetter than San Antonio. Days with measurable rain: Martha's Vineyard 39%, San Antonio 21% (n=248 and n=248 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in December, Martha's Vineyard or San Antonio?
San Antonio edges out Martha's Vineyard for sun in December: 17% clear historically versus 0% (8-year ERA5 average, a 17-point gap). Martha's Vineyard also sees measurably more rain than San Antonio this month (39% vs 21% of days). Both are viable — San Antonio is the safer bet.
Compare Martha's Vineyard vs San Antonio 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.