ERA5 almanac comparison — 8 years of real data
Charleston vs Sea Island: weather in December
Sea Island edges out Charleston for sun in December: 7% clear historically versus 2% (8-year ERA5 average, a 5-point gap). Both are viable — Sea Island is the safer bet.
Charleston
SC
- Clear days, December
- 2%
- Sample size
- n=248 days
- Avg high
- 61°F
- Early December (1st–15th)
- 1%
- Late December (16th–end)
- 3%
- Rain frequency
- 30% of days
Sea Island
GA
- Clear days, December
- 7%
- Sample size
- n=248 days
- Avg high
- 63°F
- Early December (1st–15th)
- 6%
- Late December (16th–end)
- 8%
- Rain frequency
- 24% of days
Frequently asked
Is Charleston or Sea Island warmer in December?
Sea Island runs warmer by day in December. Charleston averages highs of 61°F (highs n=248 days); Sea Island averages highs of 63°F (highs n=248 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Charleston or Sea Island in December?
Days with measurable rain: Charleston 30%, Sea Island 24% (n=248 and n=248 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in December, Charleston or Sea Island?
Sea Island edges out Charleston for sun in December: 7% clear historically versus 2% (8-year ERA5 average, a 5-point gap). Both are viable — Sea Island is the safer bet.
Compare Charleston 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.