ERA5 almanac comparison — 8 years of real data
Costa Rica — Guanacaste vs Hilton Head: weather in December
Costa Rica — Guanacaste is the clear winner for sun in December: 62% of days historically clear versus just 6% in Hilton Head — a 56-point gap across 8 years of ERA5 data. This isn't close.
Costa Rica — Guanacaste
Costa Rica
- Clear days, December
- 62%
- Sample size
- n=248 days
- Avg high
- 89°F
- Early December (1st–15th)
- 64%
- Late December (16th–end)
- 61%
- Rain frequency
- 15% of days
Hilton Head
SC
- Clear days, December
- 6%
- Sample size
- n=248 days
- Avg high
- 62°F
- Early December (1st–15th)
- 3%
- Late December (16th–end)
- 8%
- Rain frequency
- 27% of days
Frequently asked
Is Costa Rica — Guanacaste or Hilton Head warmer in December?
Costa Rica — Guanacaste runs warmer by day in December. Costa Rica — Guanacaste averages highs of 89°F (highs n=248 days); Hilton Head averages highs of 62°F (highs n=248 days) (ERA5 2018–2025). Historical averages, not a forecast.
Does it rain more in Costa Rica — Guanacaste or Hilton Head in December?
Days with measurable rain: Costa Rica — Guanacaste 15%, Hilton Head 27% (n=248 and n=248 days). ERA5 2018–2025; historical, not a forecast.
Which is sunnier in December, Costa Rica — Guanacaste or Hilton Head?
Costa Rica — Guanacaste is the clear winner for sun in December: 62% of days historically clear versus just 6% in Hilton Head — a 56-point gap across 8 years of ERA5 data. This isn't close.
Compare Costa Rica — Guanacaste vs Hilton Head 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.